pathling package

Submodules

pathling.coding module

class pathling.coding.Coding(system: str, code: str, version: str | None = None, display: str | None = None, user_selected: bool | None = None)

Bases: object

A Coding represents a code in a code system. See: https://hl7.org/fhir/R4/datatypes.html#Coding

classmethod of_snomed(code: str, version: str | None = None, display: str | None = None, user_selected: bool | None = None) → Coding

Creates a SNOMED Coding.

Parameters:

• code – the code

• version – a URI that identifies the version of the code system

• display – the display text for the Coding

• user_selected – an indicator of whether the Coding was chosen directly by the user

Returns:

a SNOMED coding with given arguments.

to_literal()

Converts a Coding into a Column that contains a Coding struct. The Coding struct Column can be used as an input to terminology functions such as member_of and translate.

Returns:

a Column containing a Coding struct

pathling.context module

class pathling.context.PathlingContext(spark: SparkSession, jpc: JavaObject)

Bases: object

Main entry point for Pathling API functionality. Should be instantiated with the PathlingContext.create() class method.

Example use:

pc = PathlingContext.create(spark)
patient_df = pc.encode(spark.read.text('ndjson_resources'), 'Patient')
patient_df.show()

classmethod create(spark: SparkSession | None = None, max_nesting_level: int | None = 3, enable_extensions: bool | None = False, enabled_open_types: Sequence[str] | None = ('boolean', 'code', 'date', 'dateTime', 'decimal', 'integer', 'string', 'Coding', 'CodeableConcept', 'Address', 'Identifier', 'Reference'), enable_terminology: bool | None = True, terminology_server_url: str | None = 'https://tx.ontoserver.csiro.au/fhir', terminology_verbose_request_logging: bool | None = False, terminology_socket_timeout: int | None = 60000, max_connections_total: int | None = 32, max_connections_per_route: int | None = 16, terminology_retry_enabled: bool | None = True, terminology_retry_count: int | None = 2, enable_cache: bool | None = True, cache_max_entries: int | None = 200000, cache_storage_type: str | None = 'memory', cache_storage_path: str | None = None, cache_default_expiry: int | None = 600, cache_override_expiry: int | None = None, token_endpoint: str | None = None, enable_auth: bool | None = False, client_id: str | None = None, client_secret: str | None = None, scope: str | None = None, token_expiry_tolerance: int | None = 120, accept_language: str | None = None, enable_delta=False) → PathlingContext

Creates a PathlingContext with the given configuration options. This should only be done once within a SparkSession - subsequent calls with different configuration may produce an error.

If no SparkSession is provided, and there is not one already present in this process - a new SparkSession will be created.

If a SparkSession is not provided, and one is already running within the current process, it will be reused - and it is assumed that the Pathling library API JAR is already on the classpath. If you are running your own cluster, make sure it is on the list of packages.

If a SparkSession is provided, it needs to include the Pathling library API JAR on its classpath. You can get the path for the JAR (which is bundled with the Python package) using the pathling.etc.find_jar method.

Parameters:

• spark – a pre-configured SparkSession instance, use this if you need to control the way that the session is set up

• max_nesting_level – controls the maximum depth of nested element data that is encoded upon import. This affects certain elements within FHIR resources that contain recursive references, e.g. QuestionnaireResponse.item.

• enable_extensions – enables support for FHIR extensions

• enabled_open_types – the list of types that are encoded within open types, such as extensions. This default list was taken from the data types that are common to extensions found in widely-used IGs, such as the US and AU base profiles. In general, you will get the best query performance by encoding your data with the shortest possible list.

• enable_terminology – enables the use of terminology functions

• terminology_server_url – the endpoint of a FHIR terminology service (R4) that the server can use to resolve terminology queries. The default server is suitable for testing purposes only.

• terminology_verbose_request_logging – setting this option to True will enable additional logging of the details of requests to the terminology service. Note that logging is subject to the Spark logging level, which you can set using SparkContext.setLogLevel. Verbose request logging is sent to the DEBUG logging level.

• terminology_socket_timeout – the maximum period (in milliseconds) that the server should wait for incoming data from the HTTP service

• max_connections_total – the maximum total number of connections for the client

• max_connections_per_route – the maximum number of connections per route for the client

• terminology_retry_enabled – controls whether terminology requests that fail for possibly transient reasons (network connections, DNS problems) should be retried

• terminology_retry_count – the number of times to retry failed terminology requests

• enable_cache – set this to false to disable caching of terminology requests (not recommended)

• cache_max_entries – sets the maximum number of entries that will be held in memory

• cache_storage_type – the type of storage to use for the terminology cache. See StorageType.

• cache_storage_path – the path on disk to use for the cache, required when cache_storage_type is disk

• cache_default_expiry – the default expiry time for cache entries (in seconds), used when the server does not provide an expiry value

• cache_override_expiry – if provided, this value overrides the expiry time provided by the terminology server

• enable_auth – enables authentication of requests to the terminology server

• token_endpoint – an OAuth2 token endpoint for use with the client credentials grant

• client_id – a client ID for use with the client credentials grant

• client_secret – a client secret for use with the client credentials grant

• scope – a scope value for use with the client credentials grant

• token_expiry_tolerance – the minimum number of seconds that a token should have before expiry when deciding whether to send it with a terminology request

• accept_language – the default value of the Accept-Language HTTP header passed to the terminology server. The value may contain multiple languages, with weighted preferences as defined in https://www.rfc-editor.org/rfc/rfc9110.html#name-accept-language. If not provided, the header is not sent. The server can use the header to return the result in the preferred language if it is able. The actual behaviour may depend on the server implementation and the code systems used.

• enable_delta – enables the use of Delta for storage of FHIR data. Only supported when no SparkSession is provided.

Returns:

a PathlingContext instance initialized with the specified configuration

encode(df: DataFrame, resource_name: str, input_type: str | None = None, column: str | None = None) → DataFrame

Takes a dataframe with a string representations of FHIR resources in the given column and encodes the resources of the given types as Spark dataframe.

Parameters:

• df – a DataFrame containing the resources to encode.

• resource_name – the name of the FHIR resource to extract (Condition, Observation, etc.)

• input_type – the mime type of input string encoding. Defaults to application/fhir+json.

• column – the column in which the resources to encode are stored. If ‘None’ then the input dataframe is assumed to have one column of type string.

Returns:

a DataFrame containing the given type of resources encoded into Spark columns

encode_bundle(df: DataFrame, resource_name: str, input_type: str | None = None, column: str | None = None) → DataFrame

Takes a dataframe with a string representations of FHIR bundles in the given column and encodes the resources of the given types as Spark dataframe.

Parameters:

• df – a DataFrame containing the bundles with the resources to encode.

• resource_name – the name of the FHIR resource to extract (Condition, Observation, etc.)

• input_type – the MIME type of the input string encoding. Defaults to application/fhir+json.

• column – the column in which the resources to encode are stored. If ‘None’ then the input dataframe is assumed to have one column of type string.

Returns:

a DataFrame containing the given type of resources encoded into Spark columns

member_of(df: DataFrame, coding_column: Column, value_set_uri: str, output_column_name: str)

Takes a dataframe with a Coding column as input. A new column is created which contains a Boolean value, indicating whether the input Coding is a member of the specified FHIR ValueSet.

Parameters:

• df – a DataFrame containing the input data

• coding_column – a Column containing a struct representation of a Coding

• value_set_uri – an identifier for a FHIR ValueSet

• output_column_name – the name of the result column

Returns:

A new dataframe with an additional column containing the result of the operation

property read: DataSources

Provides access to the instance of DataSource factory.

property spark: SparkSession

Returns the SparkSession associated with this context.

subsumes(df: DataFrame, output_column_name: str, left_coding_column: Column | None = None, right_coding_column: Column | None = None, left_coding: Coding | None = None, right_coding: Coding | None = None)

Takes a dataframe with two Coding columns. A new column is created which contains a Boolean value, indicating whether the left Coding subsumes the right Coding.

Parameters:

• df – a DataFrame containing the input data

• left_coding_column – a Column containing a struct representation of a Coding, for the left-hand side of the subsumption test

• right_coding_column – a Column containing a struct representation of a Coding, for the right-hand side of the subsumption test

• left_coding – a Coding object for the left-hand side of the subsumption test

• right_coding – a Coding object for the right-hand side of the subsumption test

• output_column_name – the name of the result column

Returns:

A new dataframe with an additional column containing the result of the operation.

translate(df: DataFrame, coding_column: Column, concept_map_uri: str, reverse: bool | None = False, equivalence: str | None = 'equivalent', target: str | None = None, output_column_name: str | None = 'result')

Takes a dataframe with a Coding column as input. A new column is created which contains the array of Codings value with translation targets from the specified FHIR ConceptMap. There may be more than one target concept for each input concept.

Parameters:

• df – a DataFrame containing the input data

• coding_column – a Column containing a struct representation of a Coding

• concept_map_uri – an identifier for a FHIR ConceptMap

• reverse – the direction to traverse the map - false results in “source to target” mappings, while true results in “target to source”

• equivalence – a comma-delimited set of values from the ConceptMapEquivalence ValueSet

• target – identifies the value set in which a translation is sought. If there is no target specified, the server should return all known translations.

• output_column_name – the name of the result column

Returns:

A new dataframe with an additional column containing the result of the operation.

version()

Returns:

The version of the Pathling library.

pathling.core module

class pathling.core.Expression(expression: str, label: str | None = None)

Bases: object

Represents an FHIRPath expression that may have an optional name/alias. To make it easier to work with expressions, uses can alias this class with their own name, for example: ‘exp’ or ‘fp’ using import and then use the alias method to create labeled expressions. For example:

` from pathling import Expression as fp fp('some FHIRPath expression').alias('some name') `

alias(label: str) → Expression

Creates a new Expression object with the specified label/alias.

Parameters:

label – The label/alias to use for the new Expression object.

Returns:

A new Expression object with the specified label/alias.

classmethod as_expression(exp_or_str: Expression | str) → Expression

Casts the specified expression or string into an Expression object.

Parameters:

exp_or_str – The expression or string to cast.

Returns:

An Expression object.

classmethod as_expression_sequence(sequence_of_exp_or_str: Sequence[Expression | str]) → Sequence[Expression]

Cast a sequence of expressions or strings into a sequence of Expression objects.

Parameters:

sequence_of_exp_or_str – The sequence of expressions or strings to cast.

Returns:

A sequence of Expression objects.

as_tuple() → Tuple

Gets a tuple representing the expression and its optional label/alias.

Returns:

A tuple representing the expression and its optional label/alias.

property expression: str

Gets the FHIRPath expression.

Returns:

The FHIRPath expression.

property label: str | None

Gets the optional label/alias for the expression.

Returns:

The optional label/alias for the expression.

class pathling.core.Function(lambda_function, spark)

Bases: object

Wraps a Python lambda function so that it can be passed to Java functions that expect a java.util.function.Function object.

Parameters:

• lambda_function – A Python lambda function that takes one argument.

• spark – A pyspark.sql.SparkSession object.

class Java

Bases: object

implements = ['java.util.function.Function']

apply(arg)

Invokes the wrapped lambda function with the given argument.

Parameters:

arg – The argument to pass to the lambda function.

Returns:

The result of the lambda function, converted to a Java object.

class pathling.core.SparkConversionsMixin(spark: SparkSession)

Bases: object

A mixin that provides access to the Spark session and a number for utility methods for converting between Python and Java objects.

property spark: SparkSession

class pathling.core.StringMapper(gateway, fn)

Bases: object

A wrapper for a Python lambda that can be passed as a Java lambda for mapping a string value to another string value.

class Java

Bases: object

implements = ['java.util.function.UnaryOperator']

apply(arg)

class pathling.core.StringToStringSetMapper(gateway, fn)

Bases: object

A wrapper for a Python lambda that can be passed as a Java lambda for mapping a string value to a list of string values.

class Java

Bases: object

implements = ['java.util.function.Function']

apply(arg)

pathling.datasink module

class pathling.datasink.DataSinks(datasource: DataSource)

Bases: SparkConversionsMixin

A class for writing FHIR data to a variety of different targets.

delta(path: str, import_mode: str | None = 'overwrite') → None

Writes the data to a directory of Delta files.

Parameters:

• path – The URI of the directory to write the files to.

• import_mode – The import mode to use when writing the data - “overwrite” will

overwrite any existing data, “merge” will merge the new data with the existing data based on resource ID.

ndjson(path: str, save_mode: str | None = 'error', file_name_mapper: Callable[[str], str] | None = None) → None

Writes the data to a directory of NDJSON files. The files will be named using the resource type and the “.ndjson” extension.

Parameters:

• path – The URI of the directory to write the files to.

• save_mode – The save mode to use when writing the data: - “overwrite” will overwrite any existing data. - “append” will append the new data to the existing data. - “ignore” will only save the data if the file does not already exist. - “error” will raise an error if the file already exists.

• file_name_mapper – An optional function that can be used to customise the mapping of

the resource type to the file name.

parquet(path: str, save_mode: str | None = 'error') → None

Writes the data to a directory of Parquet files.

Parameters:

• path – The URI of the directory to write the files to.

• save_mode – The save mode to use when writing the data: - “overwrite” will overwrite any existing data. - “append” will append the new data to the existing data. - “ignore” will only save the data if the file does not already exist. - “error” will raise an error if the file already exists.

tables(schema: str | None = None, import_mode: str | None = 'overwrite') → None

Writes the data to a set of tables in the Spark catalog.

Parameters:

• schema – The name of the schema to write the tables to.

• import_mode – The import mode to use when writing the data - “overwrite” will

overwrite any existing data, “merge” will merge the new data with the existing data based on resource ID.

class pathling.datasink.ImportMode

Bases: object

Constants that represent the different import modes.

MERGE: str = 'merge'

OVERWRITE: str = 'overwrite'

class pathling.datasink.SaveMode

Bases: object

Constants that represent the different save modes.

OVERWRITE: Overwrite any existing data. APPEND: Append the new data to the existing data. IGNORE: Only save the data if the file does not already exist. ERROR: Raise an error if the file already exists.

APPEND: str = 'append'

ERROR: str = 'error'

IGNORE: str = 'ignore'

OVERWRITE: str = 'overwrite'

pathling.datasource module

class pathling.datasource.DataSource(jds: JavaObject, pc: PathlingContext)

Bases: SparkConversionsMixin

A data source that can be used to run queries against FHIR data.

aggregate(resource_type: str, aggregations: Sequence[Expression | str], groupings: Sequence[Expression | str] | None = None, filters: Sequence[str] | None = None) → DataFrame

Runs an aggregate query for the given resource type, using the specified aggregation, grouping, and filter expressions. The context for each of the expressions is a collection of resources of the subject resource type.

For more information see: AggregateQuery

Parameters:

• resource_type – A string representing the type of FHIR resource to aggregate data from.

• aggregations – A sequence of FHIRPath expressions that calculate a summary value from each grouping. The expressions must be singular.

• groupings – An optional sequence of FHIRPath expressions that determine which groupings the resources should be counted within.

• filters – An optional sequence of FHIRPath expressions that determine whether a resource is included in the result. The expressions must evaluate to a Boolean value. Multiple filters are combined using AND logic.

Returns:

A Spark DataFrame object containing the results of the aggregate query.

extract(resource_type: str, columns: Sequence[Expression | str], filters: Sequence[str] | None = None) → DataFrame

Runs an extract query for the given resource type, using the specified columns and filters to create a tabular extract from FHIR data.

For more information see: ExtractQuery

Parameters:

• resource_type – A string representing the type of FHIR resource to extract data from.

• columns – A sequence of FHIRPath expressions that define the columns to include in the extract.

• filters – An optional sequence of FHIRPath expressions that can be evaluated against each resource in the data set to determine whether it is included within the result. The expression must evaluate to a Boolean value. Multiple filters are combined using AND logic.

Returns:

A Spark DataFrame containing the results of the extract query.

read(resource_code: str) → DataFrame

Reads the data for the given resource type from the data source.

Parameters:

resource_code – A string representing the type of FHIR resource to read data from.

Returns:

A Spark DataFrame containing the data for the given resource type.

property write: DataSinks

Provides access to a DataSinks object that can be used to persist data.

class pathling.datasource.DataSources(pathling: PathlingContext)

Bases: SparkConversionsMixin

A factory for creating data sources.

bundles(path: str, resource_types: Sequence[str], mime_type: str = 'application/fhir+json') → DataSource

Creates a data source from a directory containing FHIR bundles.

Parameters:

• path – The URI of the directory containing the bundles.

• resource_types – A sequence of resource type codes that should be extracted from the bundles.

• mime_type – The MIME type of the bundles. Defaults to application/fhir+json.

Returns:

A DataSource object that can be used to run queries against the data.

datasets(resources: Dict[str, DataFrame]) → DataSource

Creates an immutable, ad-hoc data source from a dictionary of Spark DataFrames indexed with resource type codes.

Parameters:

resources – A dictionary of Spark DataFrames, where the keys are resource type codes and the values are the data frames containing the resource data.

Returns:

A DataSource object that can be used to run queries against the data.

delta(path: str) → DataSource

Creates a data source from a directory containing Delta tables, as used by Pathling Server for persistence. Each table must be named according to the name of the resource type that it stores.

Parameters:

path – The URI of the directory containing the Delta tables.

Returns:

A DataSource object that can be used to run queries against the data.

ndjson(path, extension: str | None = 'ndjson', file_name_mapper: Callable[[str], Sequence[str]] | None = None) → DataSource

Creates a data source from a directory containing NDJSON files. The files must be named with the resource type code and must have the “.ndjson” extension, e.g. “Patient.ndjson” or “Observation.ndjson”.

Parameters:

• path – The URI of the directory containing the NDJSON files.

• extension – The file extension to use when searching for files. Defaults to “ndjson”.

• file_name_mapper – An optional function that maps a filename to the set of resource types that it contains.

Returns:

A DataSource object that can be used to run queries against the data.

parquet(path: str) → DataSource

Creates a data source from a directory containing Parquet tables. Each table must be named according to the name of the resource type that it stores.

Parameters:

path – The URI of the directory containing the Parquet tables.

Returns:

A DataSource object that can be used to run queries against the data.

tables(schema: str | None = None) → DataSource

Creates a data source from a set of Spark tables, where the table names are the resource type codes.

Parameters:

schema – An optional schema name that should be used to qualify the table names.

Returns:

A DataSource object that can be used to run queries against the data.

pathling.fhir module

class pathling.fhir.MimeType

Bases: object

Constants for FHIR encoding mime types.

FHIR_JSON: str = 'application/fhir+json'

FHIR_XML: str = 'application/fhir+xml'

class pathling.fhir.Version

Bases: object

Constants for FHIR versions.

R4: str = 'R4'

pathling.functions module

pathling.functions.to_coding(coding_column: Column, system: str, version: str | None = None) → Column

Converts a Column containing codes into a Column that contains a Coding struct. The Coding struct Column can be used as an input to terminology functions such as member_of and translate.

Parameters:

• coding_column – the Column containing the codes

• system – the URI of the system the codes belong to

• version – the version of the code system

Returns:

a Column containing a Coding struct

pathling.functions.to_ecl_value_set(ecl: str) → str

Converts a SNOMED CT ECL expression into a FHIR ValueSet URI. Can be used with the member_of function.

Parameters:

ecl – the ECL expression

Returns:

the ValueSet URI

pathling.functions.to_loinc_coding(coding_column: Column, version: str | None = None) → Column

Converts a Column containing codes into a Column that contains a LOINC Coding struct. The Coding struct Column can be used as an input to terminology functions such as member_of and translate.

Parameters:

• coding_column – the Column containing the codes

• version – the version of the code system

Returns:

a Column containing a Coding struct

pathling.functions.to_snomed_coding(coding_column: Column, version: str | None = None) → Column

Converts a Column containing codes into a Column that contains a SNOMED Coding struct. The Coding struct Column can be used as an input to terminology functions such as member_of and translate.

Parameters:

• coding_column – the Column containing the codes

• version – the version of the code system

Returns:

a Column containing a Coding struct

pathling.query module

class pathling.query.AggregateQuery(subject_resource: str, aggregations: Sequence[Expression | str], groupings: Sequence[Expression | str] | None = None, filters: Sequence[str] | None = None, data_source: DataSource | None = None)

Bases: QueryWithFilters

Represents an aggregate query for FHIR data. The query calculates summary values based on aggregations and groupings of FHIR resources.

Parameters:

• subject_resource – A string representing the type of FHIR resource to aggregate data from.

• aggregations – A sequence of FHIRPath expressions that calculate a summary value from each grouping. The expressions must be singular.

• groupings – An optional sequence of FHIRPath expressions that determine which groupings the resources should be counted within.

• filters – An optional sequence of FHIRPath expressions that determine whether a resource is included in the result. The expressions must evaluate to a Boolean value. Multiple filters are combined using AND logic.

• data_source – The DataSource object containing the data to be queried.

property aggregations: Sequence[Expression]

The sequence of FHIRPath expressions that calculate a summary value from each grouping.

Returns:

A sequence of Expression objects representing the aggregations for the query.

property groupings: Sequence[Expression] | None

The optional sequence of FHIRPath expressions that determine which groupings the resources should be counted within.

Returns:

A sequence of Expression objects representing the groupings for the query.

class pathling.query.ExtractQuery(subject_resource: str, columns: Sequence[Expression | str], filters: Sequence[str] | None, data_source: DataSource | None = None)

Bases: QueryWithFilters

Represents an extract query that extracts specified columns from FHIR resources and applies optional filters.

Parameters:

• subject_resource – A string representing the type of FHIR resource to extract data from.

• columns – A sequence of FHIRPath expressions that define the columns to include in the extract.

• filters – An optional sequence of FHIRPath expressions that can be evaluated against each resource in the data set to determine whether it is included within the result. The expression must evaluate to a Boolean value. Multiple filters are combined using AND logic.

• data_source – An optional DataSource instance to use for executing the query.

property columns: Sequence[Expression]

Gets the columns to extract.

Returns:

A sequence of Expression objects representing the columns to extract.

class pathling.query.QueryWithFilters(subject_resource: str, filters: Sequence[str] | None, data_source: DataSource | None = None)

Bases: object

Represents a query that can be executed against a data source, with the capability to filter the resources included in the result and define the subject resource type for all FHIRPath expressions in the query.

Note

This class is meant to be subclassed with an implementation of the _create_jquery method.

execute(data_source: DataSource | None = None)

Execute the query against a data source.

Parameters:

data_source (Optional[DataSource]) – The data source to execute the query against. If not provided, the query will use the data source provided to the constructor.

Returns:

A Spark DataFrame containing the query results.

property filters: Sequence[str] | None

An optional sequence of FHIRPath expressions that determine whether a resource is included in the result.

property subject_resource: str

The FHIR resource type to use as the subject for the query.

pathling.udfs module

class pathling.udfs.Equivalence

Bases: object

Concept map equivalences, see https://www.hl7.org/fhir/R4/valueset-concept-map-equivalence.html.

DISJOINT = 'disjoint'

EQUAL = 'equal'

EQUIVALENT = 'equivalent'

INEXACT = 'inexact'

NARROWER = 'narrower'

RELATEDTO = 'relatedto'

SPECIALIZES = 'specializes'

SUBSUMES = 'subsumes'

UNMATCHED = 'unmatched'

WIDER = 'wider'

class pathling.udfs.PropertyType

Bases: object

Allowed property types.

BOOLEAN = 'boolean'

CODE = 'code'

CODING = 'Coding'

DATETIME = 'dateTime'

DECIMAL = 'decimal'

INTEGER = 'integer'

STRING = 'string'

pathling.udfs.designation(coding: Column | str | Coding, use: Column | str | Coding | None = None, language: str | None = None) → Column

Takes a Coding column as its input. Returns the Column, which contains the values of designations (strings) for this coding for the specified use and language. If the language is not provided (is null) then all designations with the specified type are returned regardless of their language.

Parameters:

• coding – a Column containing a struct representation of a Coding

• use – the code with the use of the designations

• language – the language of the designations

Returns:

the Column containing the result of the operation (array of strings with designation values)

pathling.udfs.display(coding: Column | str | Coding, accept_language: str | None = None) → Column

Takes a Coding column as its input. Returns the Column, which contains the canonical display name associated with the given code.

Parameters:

• coding – a Column containing a struct representation of a Coding.

• accept_language – the optional language preferences for the returned display name. Overrides the parameter accept_language in PathlingContext.create.

Returns:

a Column containing the result of the operation (String).

pathling.udfs.member_of(coding: Column | str | Coding, value_set_uri: str) → Column

Takes a Coding or array of Codings column as its input. Returns the column which contains a Boolean value, indicating whether any of the input Codings is the member of the specified FHIR ValueSet.

Parameters:

• coding – a Column containing a struct representation of a Coding or an array of such structs.

• value_set_uri – an identifier for a FHIR ValueSet

Returns:

a Column containing the result of the operation.

pathling.udfs.property_of(coding: Column | str | Coding, property_code: str, property_type: str = 'string', accept_language: str | None = None) → Column

Takes a Coding column as its input. Returns the Column, which contains the values of properties for this coding with specified names and types. The type of the result column depends on the types of the properties. Primitive FHIR types are mapped to their corresponding SQL primitives. Complex types are mapped to their corresponding structs. The allowed property types are: code | Coding | string | integer | boolean | dateTime | decimal. See also PropertyType.

Parameters:

• coding – a Column containing a struct representation of a Coding

• property_code – the code of the property to retrieve.

• property_type – the type of the property to retrieve.

• accept_language – the optional language preferences for the returned property values. Overrides the parameter accept_language in PathlingContext.create.

Returns:

the Column containing the result of the operation (array of property values)

pathling.udfs.subsumed_by(left_coding: Column | str | Coding, right_coding: Column | str | Coding) → Column

Takes two Coding columns as input. Returns the Column, which contains a Boolean value, indicating whether the left Coding is subsumed by the right Coding.

Parameters:

• left_coding – a Column containing a struct representation of a Coding or an array of Codings.

• right_coding – a Column containing a struct representation of a Coding or an array of Codings.

Returns:

a Column containing the result of the operation (boolean).

pathling.udfs.subsumes(left_coding: Column | str | Coding, right_coding: Column | str | Coding) → Column

Takes two Coding columns as input. Returns the Column, which contains a

Boolean value, indicating whether the left Coding subsumes the right Coding.

Parameters:

• left_coding – a Column containing a struct representation of a Coding or an array of Codings.

• right_coding – a Column containing a struct representation of a Coding or an array of Codings.

Returns:

a Column containing the result of the operation (boolean).

pathling.udfs.translate(coding: Column | str | Coding, concept_map_uri: str, reverse: bool = False, equivalences: str | Collection[str] | None = None, target: str | None = None) → Column

Takes a Coding column as input. Returns the Column which contains an array of Coding value with translation targets from the specified FHIR ConceptMap. There may be more than one target concept for each input concept. Only the translation with the specified equivalences are returned. See also Equivalence. :param coding: a Column containing a struct representation of a Coding :param concept_map_uri: an identifier for a FHIR ConceptMap :param reverse: the direction to traverse the map - false results in “source to target”

mappings, while true results in “target to source”

Parameters:

• equivalences – a value of a collection of values from the ConceptMapEquivalence ValueSet

• target – identifies the value set in which a translation is sought. If there’s no target specified, the server should return all known translations.

Returns:

a Column containing the result of the operation (an array of Coding structs).

Module contents

class pathling.AggregateQuery(subject_resource: str, aggregations: Sequence[Expression | str], groupings: Sequence[Expression | str] | None = None, filters: Sequence[str] | None = None, data_source: DataSource | None = None)

Bases: QueryWithFilters

Represents an aggregate query for FHIR data. The query calculates summary values based on aggregations and groupings of FHIR resources.

Parameters:

• subject_resource – A string representing the type of FHIR resource to aggregate data from.

• aggregations – A sequence of FHIRPath expressions that calculate a summary value from each grouping. The expressions must be singular.

• groupings – An optional sequence of FHIRPath expressions that determine which groupings the resources should be counted within.

• filters – An optional sequence of FHIRPath expressions that determine whether a resource is included in the result. The expressions must evaluate to a Boolean value. Multiple filters are combined using AND logic.

• data_source – The DataSource object containing the data to be queried.

property aggregations: Sequence[Expression]

The sequence of FHIRPath expressions that calculate a summary value from each grouping.

Returns:

A sequence of Expression objects representing the aggregations for the query.

property groupings: Sequence[Expression] | None

The optional sequence of FHIRPath expressions that determine which groupings the resources should be counted within.

Returns:

A sequence of Expression objects representing the groupings for the query.

class pathling.Coding(system: str, code: str, version: str | None = None, display: str | None = None, user_selected: bool | None = None)

Bases: object

A Coding represents a code in a code system. See: https://hl7.org/fhir/R4/datatypes.html#Coding

classmethod of_snomed(code: str, version: str | None = None, display: str | None = None, user_selected: bool | None = None) → Coding

Creates a SNOMED Coding.

Parameters:

• code – the code

• version – a URI that identifies the version of the code system

• display – the display text for the Coding

• user_selected – an indicator of whether the Coding was chosen directly by the user

Returns:

a SNOMED coding with given arguments.

to_literal()

Converts a Coding into a Column that contains a Coding struct. The Coding struct Column can be used as an input to terminology functions such as member_of and translate.

Returns:

a Column containing a Coding struct

class pathling.DataSource(jds: JavaObject, pc: PathlingContext)

Bases: SparkConversionsMixin

A data source that can be used to run queries against FHIR data.

aggregate(resource_type: str, aggregations: Sequence[Expression | str], groupings: Sequence[Expression | str] | None = None, filters: Sequence[str] | None = None) → DataFrame

Runs an aggregate query for the given resource type, using the specified aggregation, grouping, and filter expressions. The context for each of the expressions is a collection of resources of the subject resource type.

For more information see: AggregateQuery

Parameters:

• resource_type – A string representing the type of FHIR resource to aggregate data from.

• aggregations – A sequence of FHIRPath expressions that calculate a summary value from each grouping. The expressions must be singular.

• groupings – An optional sequence of FHIRPath expressions that determine which groupings the resources should be counted within.

• filters – An optional sequence of FHIRPath expressions that determine whether a resource is included in the result. The expressions must evaluate to a Boolean value. Multiple filters are combined using AND logic.

Returns:

A Spark DataFrame object containing the results of the aggregate query.

extract(resource_type: str, columns: Sequence[Expression | str], filters: Sequence[str] | None = None) → DataFrame

Runs an extract query for the given resource type, using the specified columns and filters to create a tabular extract from FHIR data.

For more information see: ExtractQuery

Parameters:

• resource_type – A string representing the type of FHIR resource to extract data from.

• columns – A sequence of FHIRPath expressions that define the columns to include in the extract.

• filters – An optional sequence of FHIRPath expressions that can be evaluated against each resource in the data set to determine whether it is included within the result. The expression must evaluate to a Boolean value. Multiple filters are combined using AND logic.

Returns:

A Spark DataFrame containing the results of the extract query.

read(resource_code: str) → DataFrame

Reads the data for the given resource type from the data source.

Parameters:

resource_code – A string representing the type of FHIR resource to read data from.

Returns:

A Spark DataFrame containing the data for the given resource type.

property write: DataSinks

Provides access to a DataSinks object that can be used to persist data.

class pathling.DataSources(pathling: PathlingContext)

Bases: SparkConversionsMixin

A factory for creating data sources.

bundles(path: str, resource_types: Sequence[str], mime_type: str = 'application/fhir+json') → DataSource

Creates a data source from a directory containing FHIR bundles.

Parameters:

• path – The URI of the directory containing the bundles.

• resource_types – A sequence of resource type codes that should be extracted from the bundles.

• mime_type – The MIME type of the bundles. Defaults to application/fhir+json.

Returns:

A DataSource object that can be used to run queries against the data.

datasets(resources: Dict[str, DataFrame]) → DataSource

Creates an immutable, ad-hoc data source from a dictionary of Spark DataFrames indexed with resource type codes.

Parameters:

resources – A dictionary of Spark DataFrames, where the keys are resource type codes and the values are the data frames containing the resource data.

Returns:

A DataSource object that can be used to run queries against the data.

delta(path: str) → DataSource

Creates a data source from a directory containing Delta tables, as used by Pathling Server for persistence. Each table must be named according to the name of the resource type that it stores.

Parameters:

path – The URI of the directory containing the Delta tables.

Returns:

A DataSource object that can be used to run queries against the data.

ndjson(path, extension: str | None = 'ndjson', file_name_mapper: Callable[[str], Sequence[str]] | None = None) → DataSource

Creates a data source from a directory containing NDJSON files. The files must be named with the resource type code and must have the “.ndjson” extension, e.g. “Patient.ndjson” or “Observation.ndjson”.

Parameters:

• path – The URI of the directory containing the NDJSON files.

• extension – The file extension to use when searching for files. Defaults to “ndjson”.

• file_name_mapper – An optional function that maps a filename to the set of resource types that it contains.

Returns:

A DataSource object that can be used to run queries against the data.

parquet(path: str) → DataSource

Creates a data source from a directory containing Parquet tables. Each table must be named according to the name of the resource type that it stores.

Parameters:

path – The URI of the directory containing the Parquet tables.

Returns:

A DataSource object that can be used to run queries against the data.

tables(schema: str | None = None) → DataSource

Creates a data source from a set of Spark tables, where the table names are the resource type codes.

Parameters:

schema – An optional schema name that should be used to qualify the table names.

Returns:

A DataSource object that can be used to run queries against the data.

class pathling.Equivalence

Bases: object

Concept map equivalences, see https://www.hl7.org/fhir/R4/valueset-concept-map-equivalence.html.

DISJOINT = 'disjoint'

EQUAL = 'equal'

EQUIVALENT = 'equivalent'

INEXACT = 'inexact'

NARROWER = 'narrower'

RELATEDTO = 'relatedto'

SPECIALIZES = 'specializes'

SUBSUMES = 'subsumes'

UNMATCHED = 'unmatched'

WIDER = 'wider'

class pathling.Expression(expression: str, label: str | None = None)

Bases: object

Represents an FHIRPath expression that may have an optional name/alias. To make it easier to work with expressions, uses can alias this class with their own name, for example: ‘exp’ or ‘fp’ using import and then use the alias method to create labeled expressions. For example:

` from pathling import Expression as fp fp('some FHIRPath expression').alias('some name') `

alias(label: str) → Expression

Creates a new Expression object with the specified label/alias.

Parameters:

label – The label/alias to use for the new Expression object.

Returns:

A new Expression object with the specified label/alias.

classmethod as_expression(exp_or_str: Expression | str) → Expression

Casts the specified expression or string into an Expression object.

Parameters:

exp_or_str – The expression or string to cast.

Returns:

An Expression object.

classmethod as_expression_sequence(sequence_of_exp_or_str: Sequence[Expression | str]) → Sequence[Expression]

Cast a sequence of expressions or strings into a sequence of Expression objects.

Parameters:

sequence_of_exp_or_str – The sequence of expressions or strings to cast.

Returns:

A sequence of Expression objects.

as_tuple() → Tuple

Gets a tuple representing the expression and its optional label/alias.

Returns:

A tuple representing the expression and its optional label/alias.

property expression: str

Gets the FHIRPath expression.

Returns:

The FHIRPath expression.

property label: str | None

Gets the optional label/alias for the expression.

Returns:

The optional label/alias for the expression.

class pathling.ExtractQuery(subject_resource: str, columns: Sequence[Expression | str], filters: Sequence[str] | None, data_source: DataSource | None = None)

Bases: QueryWithFilters

Represents an extract query that extracts specified columns from FHIR resources and applies optional filters.

Parameters:

• subject_resource – A string representing the type of FHIR resource to extract data from.

• columns – A sequence of FHIRPath expressions that define the columns to include in the extract.

• filters – An optional sequence of FHIRPath expressions that can be evaluated against each resource in the data set to determine whether it is included within the result. The expression must evaluate to a Boolean value. Multiple filters are combined using AND logic.

• data_source – An optional DataSource instance to use for executing the query.

property columns: Sequence[Expression]

Gets the columns to extract.

Returns:

A sequence of Expression objects representing the columns to extract.

class pathling.MimeType

Bases: object

Constants for FHIR encoding mime types.

FHIR_JSON: str = 'application/fhir+json'

FHIR_XML: str = 'application/fhir+xml'

class pathling.PathlingContext(spark: SparkSession, jpc: JavaObject)

Bases: object

Main entry point for Pathling API functionality. Should be instantiated with the PathlingContext.create() class method.

Example use:

pc = PathlingContext.create(spark)
patient_df = pc.encode(spark.read.text('ndjson_resources'), 'Patient')
patient_df.show()

classmethod create(spark: SparkSession | None = None, max_nesting_level: int | None = 3, enable_extensions: bool | None = False, enabled_open_types: Sequence[str] | None = ('boolean', 'code', 'date', 'dateTime', 'decimal', 'integer', 'string', 'Coding', 'CodeableConcept', 'Address', 'Identifier', 'Reference'), enable_terminology: bool | None = True, terminology_server_url: str | None = 'https://tx.ontoserver.csiro.au/fhir', terminology_verbose_request_logging: bool | None = False, terminology_socket_timeout: int | None = 60000, max_connections_total: int | None = 32, max_connections_per_route: int | None = 16, terminology_retry_enabled: bool | None = True, terminology_retry_count: int | None = 2, enable_cache: bool | None = True, cache_max_entries: int | None = 200000, cache_storage_type: str | None = 'memory', cache_storage_path: str | None = None, cache_default_expiry: int | None = 600, cache_override_expiry: int | None = None, token_endpoint: str | None = None, enable_auth: bool | None = False, client_id: str | None = None, client_secret: str | None = None, scope: str | None = None, token_expiry_tolerance: int | None = 120, accept_language: str | None = None, enable_delta=False) → PathlingContext

Creates a PathlingContext with the given configuration options. This should only be done once within a SparkSession - subsequent calls with different configuration may produce an error.

If no SparkSession is provided, and there is not one already present in this process - a new SparkSession will be created.

If a SparkSession is not provided, and one is already running within the current process, it will be reused - and it is assumed that the Pathling library API JAR is already on the classpath. If you are running your own cluster, make sure it is on the list of packages.

If a SparkSession is provided, it needs to include the Pathling library API JAR on its classpath. You can get the path for the JAR (which is bundled with the Python package) using the pathling.etc.find_jar method.

Parameters:

• spark – a pre-configured SparkSession instance, use this if you need to control the way that the session is set up

• max_nesting_level –

  controls the maximum depth of nested element data that is encoded upon import. This affects certain elements within FHIR resources that contain recursive references, e.g. QuestionnaireResponse.item.

• enable_extensions – enables support for FHIR extensions

• enabled_open_types – the list of types that are encoded within open types, such as extensions. This default list was taken from the data types that are common to extensions found in widely-used IGs, such as the US and AU base profiles. In general, you will get the best query performance by encoding your data with the shortest possible list.

• enable_terminology – enables the use of terminology functions

• terminology_server_url – the endpoint of a FHIR terminology service (R4) that the server can use to resolve terminology queries. The default server is suitable for testing purposes only.

• terminology_verbose_request_logging – setting this option to True will enable additional logging of the details of requests to the terminology service. Note that logging is subject to the Spark logging level, which you can set using SparkContext.setLogLevel. Verbose request logging is sent to the DEBUG logging level.

• terminology_socket_timeout – the maximum period (in milliseconds) that the server should wait for incoming data from the HTTP service

• max_connections_total – the maximum total number of connections for the client

• max_connections_per_route – the maximum number of connections per route for the client

• terminology_retry_enabled – controls whether terminology requests that fail for possibly transient reasons (network connections, DNS problems) should be retried

• terminology_retry_count – the number of times to retry failed terminology requests

• enable_cache – set this to false to disable caching of terminology requests (not recommended)

• cache_max_entries – sets the maximum number of entries that will be held in memory

• cache_storage_type – the type of storage to use for the terminology cache. See StorageType.

• cache_storage_path – the path on disk to use for the cache, required when cache_storage_type is disk

• cache_default_expiry – the default expiry time for cache entries (in seconds), used when the server does not provide an expiry value

• cache_override_expiry – if provided, this value overrides the expiry time provided by the terminology server

• enable_auth – enables authentication of requests to the terminology server

• token_endpoint – an OAuth2 token endpoint for use with the client credentials grant

• client_id – a client ID for use with the client credentials grant

• client_secret – a client secret for use with the client credentials grant

• scope – a scope value for use with the client credentials grant

• token_expiry_tolerance – the minimum number of seconds that a token should have before expiry when deciding whether to send it with a terminology request

• accept_language – the default value of the Accept-Language HTTP header passed to the terminology server. The value may contain multiple languages, with weighted preferences as defined in https://www.rfc-editor.org/rfc/rfc9110.html#name-accept-language. If not provided, the header is not sent. The server can use the header to return the result in the preferred language if it is able. The actual behaviour may depend on the server implementation and the code systems used.

• enable_delta – enables the use of Delta for storage of FHIR data. Only supported when no SparkSession is provided.

Returns:

a PathlingContext instance initialized with the specified configuration

encode(df: DataFrame, resource_name: str, input_type: str | None = None, column: str | None = None) → DataFrame

Takes a dataframe with a string representations of FHIR resources in the given column and encodes the resources of the given types as Spark dataframe.

Parameters:

• df – a DataFrame containing the resources to encode.

• resource_name – the name of the FHIR resource to extract (Condition, Observation, etc.)

• input_type – the mime type of input string encoding. Defaults to application/fhir+json.

• column – the column in which the resources to encode are stored. If ‘None’ then the input dataframe is assumed to have one column of type string.

Returns:

a DataFrame containing the given type of resources encoded into Spark columns

encode_bundle(df: DataFrame, resource_name: str, input_type: str | None = None, column: str | None = None) → DataFrame

Takes a dataframe with a string representations of FHIR bundles in the given column and encodes the resources of the given types as Spark dataframe.

Parameters:

• df – a DataFrame containing the bundles with the resources to encode.

• resource_name – the name of the FHIR resource to extract (Condition, Observation, etc.)

• input_type – the MIME type of the input string encoding. Defaults to application/fhir+json.

• column – the column in which the resources to encode are stored. If ‘None’ then the input dataframe is assumed to have one column of type string.

Returns:

a DataFrame containing the given type of resources encoded into Spark columns

member_of(df: DataFrame, coding_column: Column, value_set_uri: str, output_column_name: str)

Takes a dataframe with a Coding column as input. A new column is created which contains a Boolean value, indicating whether the input Coding is a member of the specified FHIR ValueSet.

Parameters:

• df – a DataFrame containing the input data

• coding_column – a Column containing a struct representation of a Coding

• value_set_uri – an identifier for a FHIR ValueSet

• output_column_name – the name of the result column

Returns:

A new dataframe with an additional column containing the result of the operation

property read: DataSources

Provides access to the instance of DataSource factory.

property spark: SparkSession

Returns the SparkSession associated with this context.

subsumes(df: DataFrame, output_column_name: str, left_coding_column: Column | None = None, right_coding_column: Column | None = None, left_coding: Coding | None = None, right_coding: Coding | None = None)

Takes a dataframe with two Coding columns. A new column is created which contains a Boolean value, indicating whether the left Coding subsumes the right Coding.

Parameters:

• df – a DataFrame containing the input data

• left_coding_column – a Column containing a struct representation of a Coding, for the left-hand side of the subsumption test

• right_coding_column – a Column containing a struct representation of a Coding, for the right-hand side of the subsumption test

• left_coding – a Coding object for the left-hand side of the subsumption test

• right_coding – a Coding object for the right-hand side of the subsumption test

• output_column_name – the name of the result column

Returns:

A new dataframe with an additional column containing the result of the operation.

translate(df: DataFrame, coding_column: Column, concept_map_uri: str, reverse: bool | None = False, equivalence: str | None = 'equivalent', target: str | None = None, output_column_name: str | None = 'result')

Takes a dataframe with a Coding column as input. A new column is created which contains the array of Codings value with translation targets from the specified FHIR ConceptMap. There may be more than one target concept for each input concept.

Parameters:

• df – a DataFrame containing the input data

• coding_column – a Column containing a struct representation of a Coding

• concept_map_uri – an identifier for a FHIR ConceptMap

• reverse – the direction to traverse the map - false results in “source to target” mappings, while true results in “target to source”

• equivalence – a comma-delimited set of values from the ConceptMapEquivalence ValueSet

• target – identifies the value set in which a translation is sought. If there is no target specified, the server should return all known translations.

• output_column_name – the name of the result column

Returns:

A new dataframe with an additional column containing the result of the operation.

version()

Returns:

The version of the Pathling library.

class pathling.PropertyType

Bases: object

Allowed property types.

BOOLEAN = 'boolean'

CODE = 'code'

CODING = 'Coding'

DATETIME = 'dateTime'

DECIMAL = 'decimal'

INTEGER = 'integer'

STRING = 'string'

class pathling.StorageType

Bases: object

DISK: str = 'disk'

MEMORY: str = 'memory'

class pathling.Version

Bases: object

Constants for FHIR versions.

R4: str = 'R4'

pathling.designation(coding: Column | str | Coding, use: Column | str | Coding | None = None, language: str | None = None) → Column

Takes a Coding column as its input. Returns the Column, which contains the values of designations (strings) for this coding for the specified use and language. If the language is not provided (is null) then all designations with the specified type are returned regardless of their language.

Parameters:

• coding – a Column containing a struct representation of a Coding

• use – the code with the use of the designations

• language – the language of the designations

Returns:

the Column containing the result of the operation (array of strings with designation values)

pathling.display(coding: Column | str | Coding, accept_language: str | None = None) → Column

Takes a Coding column as its input. Returns the Column, which contains the canonical display name associated with the given code.

Parameters:

• coding – a Column containing a struct representation of a Coding.

• accept_language – the optional language preferences for the returned display name. Overrides the parameter accept_language in PathlingContext.create.

Returns:

a Column containing the result of the operation (String).

pathling.member_of(coding: Column | str | Coding, value_set_uri: str) → Column

Takes a Coding or array of Codings column as its input. Returns the column which contains a Boolean value, indicating whether any of the input Codings is the member of the specified FHIR ValueSet.

Parameters:

• coding – a Column containing a struct representation of a Coding or an array of such structs.

• value_set_uri – an identifier for a FHIR ValueSet

Returns:

a Column containing the result of the operation.

pathling.property_of(coding: Column | str | Coding, property_code: str, property_type: str = 'string', accept_language: str | None = None) → Column

Takes a Coding column as its input. Returns the Column, which contains the values of properties for this coding with specified names and types. The type of the result column depends on the types of the properties. Primitive FHIR types are mapped to their corresponding SQL primitives. Complex types are mapped to their corresponding structs. The allowed property types are: code | Coding | string | integer | boolean | dateTime | decimal. See also PropertyType.

Parameters:

• coding – a Column containing a struct representation of a Coding

• property_code – the code of the property to retrieve.

• property_type – the type of the property to retrieve.

• accept_language – the optional language preferences for the returned property values. Overrides the parameter accept_language in PathlingContext.create.

Returns:

the Column containing the result of the operation (array of property values)

pathling.subsumed_by(left_coding: Column | str | Coding, right_coding: Column | str | Coding) → Column

Takes two Coding columns as input. Returns the Column, which contains a Boolean value, indicating whether the left Coding is subsumed by the right Coding.

Parameters:

• left_coding – a Column containing a struct representation of a Coding or an array of Codings.

• right_coding – a Column containing a struct representation of a Coding or an array of Codings.

Returns:

a Column containing the result of the operation (boolean).

pathling.subsumes(left_coding: Column | str | Coding, right_coding: Column | str | Coding) → Column

Takes two Coding columns as input. Returns the Column, which contains a

Boolean value, indicating whether the left Coding subsumes the right Coding.

Parameters:

• left_coding – a Column containing a struct representation of a Coding or an array of Codings.

• right_coding – a Column containing a struct representation of a Coding or an array of Codings.

Returns:

a Column containing the result of the operation (boolean).

pathling.to_coding(coding_column: Column, system: str, version: str | None = None) → Column

Converts a Column containing codes into a Column that contains a Coding struct. The Coding struct Column can be used as an input to terminology functions such as member_of and translate.

Parameters:

• coding_column – the Column containing the codes

• system – the URI of the system the codes belong to

• version – the version of the code system

Returns:

a Column containing a Coding struct

pathling.to_ecl_value_set(ecl: str) → str

Converts a SNOMED CT ECL expression into a FHIR ValueSet URI. Can be used with the member_of function.

Parameters:

ecl – the ECL expression

Returns:

the ValueSet URI

pathling.to_snomed_coding(coding_column: Column, version: str | None = None) → Column

Converts a Column containing codes into a Column that contains a SNOMED Coding struct. The Coding struct Column can be used as an input to terminology functions such as member_of and translate.

Parameters:

• coding_column – the Column containing the codes

• version – the version of the code system

Returns:

a Column containing a Coding struct

pathling.translate(coding: Column | str | Coding, concept_map_uri: str, reverse: bool = False, equivalences: str | Collection[str] | None = None, target: str | None = None) → Column

Takes a Coding column as input. Returns the Column which contains an array of Coding value with translation targets from the specified FHIR ConceptMap. There may be more than one target concept for each input concept. Only the translation with the specified equivalences are returned. See also Equivalence. :param coding: a Column containing a struct representation of a Coding :param concept_map_uri: an identifier for a FHIR ConceptMap :param reverse: the direction to traverse the map - false results in “source to target”

mappings, while true results in “target to source”

Parameters:

• equivalences – a value of a collection of values from the ConceptMapEquivalence ValueSet

• target – identifies the value set in which a translation is sought. If there’s no target specified, the server should return all known translations.

Returns:

a Column containing the result of the operation (an array of Coding structs).