This documentation is for an old version of OpenDP.

The current release of OpenDP is v0.11.1.

Source code for opendp.core

# Auto-generated. Do not edit!
'''
The ``core`` module provides functions for accessing the fields of transformations and measurements.
For more context, see :ref:`core in the User Guide <core-user-guide>`.

For convenience, all the functions of this module are also available from :py:mod:`opendp.prelude`.
We suggest importing under the conventional name ``dp``:

.. code:: python

    >>> import opendp.prelude as dp
'''
from opendp._convert import *
from opendp._lib import *
from opendp.mod import *
from opendp.typing import *

__all__ = [
    "_error_free",
    "_function_free",
    "_measurement_free",
    "_transformation_free",
    "function_eval",
    "measurement_check",
    "measurement_function",
    "measurement_input_carrier_type",
    "measurement_input_distance_type",
    "measurement_input_domain",
    "measurement_input_metric",
    "measurement_invoke",
    "measurement_map",
    "measurement_output_distance_type",
    "measurement_output_measure",
    "new_function",
    "new_queryable",
    "queryable_eval",
    "queryable_query_type",
    "transformation_check",
    "transformation_function",
    "transformation_input_carrier_type",
    "transformation_input_distance_type",
    "transformation_input_domain",
    "transformation_input_metric",
    "transformation_invoke",
    "transformation_map",
    "transformation_output_distance_type",
    "transformation_output_domain",
    "transformation_output_metric"
]


def _error_free(
    this
) -> bool:
    r"""Internal function. Free the memory associated with `error`.

    :param this: 
    :type this: FfiError
    :return: A boolean, where true indicates successful free
    :rtype: bool
    :raises TypeError: if an argument's type differs from the expected type
    :raises UnknownTypeException: if a type argument fails to parse
    """
    # No type arguments to standardize.
    # Convert arguments to c types.
    c_this = this

    # Call library function.
    lib_function = lib.opendp_core___error_free
    lib_function.argtypes = [ctypes.POINTER(FfiError)]
    lib_function.restype = ctypes.c_bool

    output = c_to_py(lib_function(c_this))

    return output


def _function_free(
    this
):
    r"""Internal function. Free the memory associated with `this`.

    :param this: 
    :type this: Function
    :raises TypeError: if an argument's type differs from the expected type
    :raises UnknownTypeException: if a type argument fails to parse
    :raises OpenDPException: packaged error from the core OpenDP library
    """
    # No type arguments to standardize.
    # Convert arguments to c types.
    c_this = this

    # Call library function.
    lib_function = lib.opendp_core___function_free
    lib_function.argtypes = [Function]
    lib_function.restype = FfiResult

    output = c_to_py(unwrap(lib_function(c_this), ctypes.c_void_p))

    return output


def _measurement_free(
    this
):
    r"""Internal function. Free the memory associated with `this`.

    :param this: 
    :type this: Measurement
    :raises TypeError: if an argument's type differs from the expected type
    :raises UnknownTypeException: if a type argument fails to parse
    :raises OpenDPException: packaged error from the core OpenDP library
    """
    # No type arguments to standardize.
    # Convert arguments to c types.
    c_this = this

    # Call library function.
    lib_function = lib.opendp_core___measurement_free
    lib_function.argtypes = [Measurement]
    lib_function.restype = FfiResult

    output = c_to_py(unwrap(lib_function(c_this), ctypes.c_void_p))

    return output


def _transformation_free(
    this
):
    r"""Internal function. Free the memory associated with `this`.

    :param this: 
    :type this: Transformation
    :raises TypeError: if an argument's type differs from the expected type
    :raises UnknownTypeException: if a type argument fails to parse
    :raises OpenDPException: packaged error from the core OpenDP library
    """
    # No type arguments to standardize.
    # Convert arguments to c types.
    c_this = this

    # Call library function.
    lib_function = lib.opendp_core___transformation_free
    lib_function.argtypes = [Transformation]
    lib_function.restype = FfiResult

    output = c_to_py(unwrap(lib_function(c_this), ctypes.c_void_p))

    return output


[docs] def function_eval( this: Function, arg, TI: Optional[str] = None ): r"""Eval the `function` with `arg`. :param this: Function to invoke. :type this: Function :param arg: Input data to supply to the measurement. A member of the measurement's input domain. :param TI: Input Type. :type TI: str :raises TypeError: if an argument's type differs from the expected type :raises UnknownTypeException: if a type argument fails to parse :raises OpenDPException: packaged error from the core OpenDP library """ # No type arguments to standardize. # Convert arguments to c types. c_this = py_to_c(this, c_type=Function, type_name=None) c_arg = py_to_c(arg, c_type=AnyObjectPtr, type_name=parse_or_infer(TI, arg)) c_TI = py_to_c(TI, c_type=ctypes.c_char_p, type_name=None) # Call library function. lib_function = lib.opendp_core__function_eval lib_function.argtypes = [Function, AnyObjectPtr, ctypes.c_char_p] lib_function.restype = FfiResult output = c_to_py(unwrap(lib_function(c_this, c_arg, c_TI), AnyObjectPtr)) return output
[docs] def measurement_check( measurement: Measurement, distance_in, distance_out ): r"""Check the privacy relation of the `measurement` at the given `d_in`, `d_out` :param measurement: Measurement to check the privacy relation of. :type measurement: Measurement :param distance_in: :param distance_out: :return: True indicates that the relation passed at the given distance. :raises TypeError: if an argument's type differs from the expected type :raises UnknownTypeException: if a type argument fails to parse :raises OpenDPException: packaged error from the core OpenDP library """ # No type arguments to standardize. # Convert arguments to c types. c_measurement = py_to_c(measurement, c_type=Measurement, type_name=None) c_distance_in = py_to_c(distance_in, c_type=AnyObjectPtr, type_name=measurement_input_distance_type(measurement)) c_distance_out = py_to_c(distance_out, c_type=AnyObjectPtr, type_name=measurement_output_distance_type(measurement)) # Call library function. lib_function = lib.opendp_core__measurement_check lib_function.argtypes = [Measurement, AnyObjectPtr, AnyObjectPtr] lib_function.restype = FfiResult output = c_to_py(unwrap(lib_function(c_measurement, c_distance_in, c_distance_out), BoolPtr)) return output
[docs] def measurement_function( this: Measurement ) -> Function: r"""Get the function from a measurement. :param this: The measurement to retrieve the value from. :type this: Measurement :rtype: Function :raises TypeError: if an argument's type differs from the expected type :raises UnknownTypeException: if a type argument fails to parse :raises OpenDPException: packaged error from the core OpenDP library """ # No type arguments to standardize. # Convert arguments to c types. c_this = py_to_c(this, c_type=Measurement, type_name=None) # Call library function. lib_function = lib.opendp_core__measurement_function lib_function.argtypes = [Measurement] lib_function.restype = FfiResult output = unwrap(lib_function(c_this), Function) return output
[docs] def measurement_input_carrier_type( this: Measurement ) -> str: r"""Get the input (carrier) data type of `this`. :param this: The measurement to retrieve the type from. :type this: Measurement :rtype: str :raises TypeError: if an argument's type differs from the expected type :raises UnknownTypeException: if a type argument fails to parse :raises OpenDPException: packaged error from the core OpenDP library """ # No type arguments to standardize. # Convert arguments to c types. c_this = py_to_c(this, c_type=Measurement, type_name=None) # Call library function. lib_function = lib.opendp_core__measurement_input_carrier_type lib_function.argtypes = [Measurement] lib_function.restype = FfiResult output = c_to_py(unwrap(lib_function(c_this), ctypes.c_char_p)) return output
[docs] def measurement_input_distance_type( this: Measurement ) -> str: r"""Get the input distance type of `measurement`. :param this: The measurement to retrieve the type from. :type this: Measurement :rtype: str :raises TypeError: if an argument's type differs from the expected type :raises UnknownTypeException: if a type argument fails to parse :raises OpenDPException: packaged error from the core OpenDP library """ # No type arguments to standardize. # Convert arguments to c types. c_this = py_to_c(this, c_type=Measurement, type_name=None) # Call library function. lib_function = lib.opendp_core__measurement_input_distance_type lib_function.argtypes = [Measurement] lib_function.restype = FfiResult output = c_to_py(unwrap(lib_function(c_this), ctypes.c_char_p)) return output
[docs] def measurement_input_domain( this: Measurement ) -> Domain: r"""Get the input domain from a `measurement`. :param this: The measurement to retrieve the value from. :type this: Measurement :rtype: Domain :raises TypeError: if an argument's type differs from the expected type :raises UnknownTypeException: if a type argument fails to parse :raises OpenDPException: packaged error from the core OpenDP library """ # No type arguments to standardize. # Convert arguments to c types. c_this = py_to_c(this, c_type=Measurement, type_name=None) # Call library function. lib_function = lib.opendp_core__measurement_input_domain lib_function.argtypes = [Measurement] lib_function.restype = FfiResult output = unwrap(lib_function(c_this), Domain) return output
[docs] def measurement_input_metric( this: Measurement ) -> Metric: r"""Get the input domain from a `measurement`. :param this: The measurement to retrieve the value from. :type this: Measurement :rtype: Metric :raises TypeError: if an argument's type differs from the expected type :raises UnknownTypeException: if a type argument fails to parse :raises OpenDPException: packaged error from the core OpenDP library """ # No type arguments to standardize. # Convert arguments to c types. c_this = py_to_c(this, c_type=Measurement, type_name=None) # Call library function. lib_function = lib.opendp_core__measurement_input_metric lib_function.argtypes = [Measurement] lib_function.restype = FfiResult output = unwrap(lib_function(c_this), Metric) return output
[docs] def measurement_invoke( this: Measurement, arg ): r"""Invoke the `measurement` with `arg`. Returns a differentially private release. :param this: Measurement to invoke. :type this: Measurement :param arg: Input data to supply to the measurement. A member of the measurement's input domain. :raises TypeError: if an argument's type differs from the expected type :raises UnknownTypeException: if a type argument fails to parse :raises OpenDPException: packaged error from the core OpenDP library """ # No type arguments to standardize. # Convert arguments to c types. c_this = py_to_c(this, c_type=Measurement, type_name=None) c_arg = py_to_c(arg, c_type=AnyObjectPtr, type_name=measurement_input_carrier_type(this)) # Call library function. lib_function = lib.opendp_core__measurement_invoke lib_function.argtypes = [Measurement, AnyObjectPtr] lib_function.restype = FfiResult output = c_to_py(unwrap(lib_function(c_this, c_arg), AnyObjectPtr)) return output
[docs] def measurement_map( measurement: Measurement, distance_in ): r"""Use the `measurement` to map a given `d_in` to `d_out`. :param measurement: Measurement to check the map distances with. :type measurement: Measurement :param distance_in: Distance in terms of the input metric. :raises TypeError: if an argument's type differs from the expected type :raises UnknownTypeException: if a type argument fails to parse :raises OpenDPException: packaged error from the core OpenDP library """ # No type arguments to standardize. # Convert arguments to c types. c_measurement = py_to_c(measurement, c_type=Measurement, type_name=None) c_distance_in = py_to_c(distance_in, c_type=AnyObjectPtr, type_name=measurement_input_distance_type(measurement)) # Call library function. lib_function = lib.opendp_core__measurement_map lib_function.argtypes = [Measurement, AnyObjectPtr] lib_function.restype = FfiResult output = c_to_py(unwrap(lib_function(c_measurement, c_distance_in), AnyObjectPtr)) return output
[docs] def measurement_output_distance_type( this: Measurement ) -> str: r"""Get the output distance type of `measurement`. :param this: The measurement to retrieve the type from. :type this: Measurement :rtype: str :raises TypeError: if an argument's type differs from the expected type :raises UnknownTypeException: if a type argument fails to parse :raises OpenDPException: packaged error from the core OpenDP library """ # No type arguments to standardize. # Convert arguments to c types. c_this = py_to_c(this, c_type=Measurement, type_name=None) # Call library function. lib_function = lib.opendp_core__measurement_output_distance_type lib_function.argtypes = [Measurement] lib_function.restype = FfiResult output = c_to_py(unwrap(lib_function(c_this), ctypes.c_char_p)) return output
[docs] def measurement_output_measure( this: Measurement ) -> Measure: r"""Get the output domain from a `measurement`. :param this: The measurement to retrieve the value from. :type this: Measurement :rtype: Measure :raises TypeError: if an argument's type differs from the expected type :raises UnknownTypeException: if a type argument fails to parse :raises OpenDPException: packaged error from the core OpenDP library """ # No type arguments to standardize. # Convert arguments to c types. c_this = py_to_c(this, c_type=Measurement, type_name=None) # Call library function. lib_function = lib.opendp_core__measurement_output_measure lib_function.argtypes = [Measurement] lib_function.restype = FfiResult output = unwrap(lib_function(c_this), Measure) return output
[docs] def new_function( function, TO: RuntimeTypeDescriptor ) -> Function: r"""Construct a Function from a user-defined callback. Can be used as a post-processing step. :param function: A function mapping data to a value of type `TO` :param TO: Output Type :type TO: :py:ref:`RuntimeTypeDescriptor` :rtype: Function :raises TypeError: if an argument's type differs from the expected type :raises UnknownTypeException: if a type argument fails to parse :raises OpenDPException: packaged error from the core OpenDP library """ assert_features("contrib") # Standardize type arguments. TO = RuntimeType.parse(type_name=TO) # Convert arguments to c types. c_function = py_to_c(function, c_type=CallbackFn, type_name=pass_through(TO)) c_TO = py_to_c(TO, c_type=ctypes.c_char_p) # Call library function. lib_function = lib.opendp_core__new_function lib_function.argtypes = [CallbackFn, ctypes.c_char_p] lib_function.restype = FfiResult output = c_to_py(unwrap(lib_function(c_function, c_TO), Function)) output._depends_on(c_function) return output
[docs] def new_queryable( transition, Q: RuntimeTypeDescriptor = "ExtrinsicObject", A: RuntimeTypeDescriptor = "ExtrinsicObject" ): r"""Construct a queryable from a user-defined transition function. :param transition: A transition function taking a reference to self, a query, and an internal/external indicator :param Q: Query Type :type Q: :py:ref:`RuntimeTypeDescriptor` :param A: Output Type :type A: :py:ref:`RuntimeTypeDescriptor` :raises TypeError: if an argument's type differs from the expected type :raises UnknownTypeException: if a type argument fails to parse :raises OpenDPException: packaged error from the core OpenDP library """ assert_features("contrib") # Standardize type arguments. Q = RuntimeType.parse(type_name=Q) A = RuntimeType.parse(type_name=A) # Convert arguments to c types. c_transition = py_to_c(transition, c_type=TransitionFn, type_name=pass_through(A)) c_Q = py_to_c(Q, c_type=ctypes.c_char_p) c_A = py_to_c(A, c_type=ctypes.c_char_p) # Call library function. lib_function = lib.opendp_core__new_queryable lib_function.argtypes = [TransitionFn, ctypes.c_char_p, ctypes.c_char_p] lib_function.restype = FfiResult output = c_to_py(unwrap(lib_function(c_transition, c_Q, c_A), AnyObjectPtr)) output._depends_on(c_transition) return output
[docs] def queryable_eval( queryable, query ): r"""Invoke the `queryable` with `query`. Returns a differentially private release. :param queryable: Queryable to eval. :param query: Input data to supply to the measurement. A member of the measurement's input domain. :raises TypeError: if an argument's type differs from the expected type :raises UnknownTypeException: if a type argument fails to parse :raises OpenDPException: packaged error from the core OpenDP library """ # No type arguments to standardize. # Convert arguments to c types. c_queryable = py_to_c(queryable, c_type=AnyObjectPtr, type_name=None) c_query = py_to_c(query, c_type=AnyObjectPtr, type_name=queryable_query_type(queryable)) # Call library function. lib_function = lib.opendp_core__queryable_eval lib_function.argtypes = [AnyObjectPtr, AnyObjectPtr] lib_function.restype = FfiResult output = c_to_py(unwrap(lib_function(c_queryable, c_query), AnyObjectPtr)) return output
[docs] def queryable_query_type( this ) -> str: r"""Get the query type of `queryable`. :param this: The queryable to retrieve the query type from. :rtype: str :raises TypeError: if an argument's type differs from the expected type :raises UnknownTypeException: if a type argument fails to parse :raises OpenDPException: packaged error from the core OpenDP library """ # No type arguments to standardize. # Convert arguments to c types. c_this = py_to_c(this, c_type=AnyObjectPtr, type_name=None) # Call library function. lib_function = lib.opendp_core__queryable_query_type lib_function.argtypes = [AnyObjectPtr] lib_function.restype = FfiResult output = c_to_py(unwrap(lib_function(c_this), ctypes.c_char_p)) return output
[docs] def transformation_check( transformation: Transformation, distance_in, distance_out ): r"""Check the privacy relation of the `measurement` at the given `d_in`, `d_out` :param transformation: :type transformation: Transformation :param distance_in: :param distance_out: :return: True indicates that the relation passed at the given distance. :raises TypeError: if an argument's type differs from the expected type :raises UnknownTypeException: if a type argument fails to parse :raises OpenDPException: packaged error from the core OpenDP library """ # No type arguments to standardize. # Convert arguments to c types. c_transformation = py_to_c(transformation, c_type=Transformation, type_name=None) c_distance_in = py_to_c(distance_in, c_type=AnyObjectPtr, type_name=transformation_input_distance_type(transformation)) c_distance_out = py_to_c(distance_out, c_type=AnyObjectPtr, type_name=transformation_output_distance_type(transformation)) # Call library function. lib_function = lib.opendp_core__transformation_check lib_function.argtypes = [Transformation, AnyObjectPtr, AnyObjectPtr] lib_function.restype = FfiResult output = c_to_py(unwrap(lib_function(c_transformation, c_distance_in, c_distance_out), BoolPtr)) return output
[docs] def transformation_function( this: Transformation ) -> Function: r"""Get the function from a transformation. :param this: The transformation to retrieve the value from. :type this: Transformation :rtype: Function :raises TypeError: if an argument's type differs from the expected type :raises UnknownTypeException: if a type argument fails to parse :raises OpenDPException: packaged error from the core OpenDP library """ # No type arguments to standardize. # Convert arguments to c types. c_this = py_to_c(this, c_type=Transformation, type_name=None) # Call library function. lib_function = lib.opendp_core__transformation_function lib_function.argtypes = [Transformation] lib_function.restype = FfiResult output = unwrap(lib_function(c_this), Function) return output
[docs] def transformation_input_carrier_type( this: Transformation ) -> str: r"""Get the input (carrier) data type of `this`. :param this: The transformation to retrieve the type from. :type this: Transformation :rtype: str :raises TypeError: if an argument's type differs from the expected type :raises UnknownTypeException: if a type argument fails to parse :raises OpenDPException: packaged error from the core OpenDP library """ # No type arguments to standardize. # Convert arguments to c types. c_this = py_to_c(this, c_type=Transformation, type_name=None) # Call library function. lib_function = lib.opendp_core__transformation_input_carrier_type lib_function.argtypes = [Transformation] lib_function.restype = FfiResult output = c_to_py(unwrap(lib_function(c_this), ctypes.c_char_p)) return output
[docs] def transformation_input_distance_type( this: Transformation ) -> str: r"""Get the input distance type of `transformation`. :param this: The transformation to retrieve the type from. :type this: Transformation :rtype: str :raises TypeError: if an argument's type differs from the expected type :raises UnknownTypeException: if a type argument fails to parse :raises OpenDPException: packaged error from the core OpenDP library """ # No type arguments to standardize. # Convert arguments to c types. c_this = py_to_c(this, c_type=Transformation, type_name=None) # Call library function. lib_function = lib.opendp_core__transformation_input_distance_type lib_function.argtypes = [Transformation] lib_function.restype = FfiResult output = c_to_py(unwrap(lib_function(c_this), ctypes.c_char_p)) return output
[docs] def transformation_input_domain( this: Transformation ) -> Domain: r"""Get the input domain from a `transformation`. :param this: The transformation to retrieve the value from. :type this: Transformation :rtype: Domain :raises TypeError: if an argument's type differs from the expected type :raises UnknownTypeException: if a type argument fails to parse :raises OpenDPException: packaged error from the core OpenDP library """ # No type arguments to standardize. # Convert arguments to c types. c_this = py_to_c(this, c_type=Transformation, type_name=None) # Call library function. lib_function = lib.opendp_core__transformation_input_domain lib_function.argtypes = [Transformation] lib_function.restype = FfiResult output = unwrap(lib_function(c_this), Domain) return output
[docs] def transformation_input_metric( this: Transformation ) -> Metric: r"""Get the input domain from a `transformation`. :param this: The transformation to retrieve the value from. :type this: Transformation :rtype: Metric :raises TypeError: if an argument's type differs from the expected type :raises UnknownTypeException: if a type argument fails to parse :raises OpenDPException: packaged error from the core OpenDP library """ # No type arguments to standardize. # Convert arguments to c types. c_this = py_to_c(this, c_type=Transformation, type_name=None) # Call library function. lib_function = lib.opendp_core__transformation_input_metric lib_function.argtypes = [Transformation] lib_function.restype = FfiResult output = unwrap(lib_function(c_this), Metric) return output
[docs] def transformation_invoke( this: Transformation, arg ): r"""Invoke the `transformation` with `arg`. Returns a differentially private release. :param this: Transformation to invoke. :type this: Transformation :param arg: Input data to supply to the transformation. A member of the transformation's input domain. :raises TypeError: if an argument's type differs from the expected type :raises UnknownTypeException: if a type argument fails to parse :raises OpenDPException: packaged error from the core OpenDP library """ # No type arguments to standardize. # Convert arguments to c types. c_this = py_to_c(this, c_type=Transformation, type_name=None) c_arg = py_to_c(arg, c_type=AnyObjectPtr, type_name=transformation_input_carrier_type(this)) # Call library function. lib_function = lib.opendp_core__transformation_invoke lib_function.argtypes = [Transformation, AnyObjectPtr] lib_function.restype = FfiResult output = c_to_py(unwrap(lib_function(c_this, c_arg), AnyObjectPtr)) return output
[docs] def transformation_map( transformation: Transformation, distance_in ): r"""Use the `transformation` to map a given `d_in` to `d_out`. :param transformation: Transformation to check the map distances with. :type transformation: Transformation :param distance_in: Distance in terms of the input metric. :raises TypeError: if an argument's type differs from the expected type :raises UnknownTypeException: if a type argument fails to parse :raises OpenDPException: packaged error from the core OpenDP library """ # No type arguments to standardize. # Convert arguments to c types. c_transformation = py_to_c(transformation, c_type=Transformation, type_name=None) c_distance_in = py_to_c(distance_in, c_type=AnyObjectPtr, type_name=transformation_input_distance_type(transformation)) # Call library function. lib_function = lib.opendp_core__transformation_map lib_function.argtypes = [Transformation, AnyObjectPtr] lib_function.restype = FfiResult output = c_to_py(unwrap(lib_function(c_transformation, c_distance_in), AnyObjectPtr)) return output
[docs] def transformation_output_distance_type( this: Transformation ) -> str: r"""Get the output distance type of `transformation`. :param this: The transformation to retrieve the type from. :type this: Transformation :rtype: str :raises TypeError: if an argument's type differs from the expected type :raises UnknownTypeException: if a type argument fails to parse :raises OpenDPException: packaged error from the core OpenDP library """ # No type arguments to standardize. # Convert arguments to c types. c_this = py_to_c(this, c_type=Transformation, type_name=None) # Call library function. lib_function = lib.opendp_core__transformation_output_distance_type lib_function.argtypes = [Transformation] lib_function.restype = FfiResult output = c_to_py(unwrap(lib_function(c_this), ctypes.c_char_p)) return output
[docs] def transformation_output_domain( this: Transformation ) -> Domain: r"""Get the output domain from a `transformation`. :param this: The transformation to retrieve the value from. :type this: Transformation :rtype: Domain :raises TypeError: if an argument's type differs from the expected type :raises UnknownTypeException: if a type argument fails to parse :raises OpenDPException: packaged error from the core OpenDP library """ # No type arguments to standardize. # Convert arguments to c types. c_this = py_to_c(this, c_type=Transformation, type_name=None) # Call library function. lib_function = lib.opendp_core__transformation_output_domain lib_function.argtypes = [Transformation] lib_function.restype = FfiResult output = unwrap(lib_function(c_this), Domain) return output
[docs] def transformation_output_metric( this: Transformation ) -> Metric: r"""Get the output domain from a `transformation`. :param this: The transformation to retrieve the value from. :type this: Transformation :rtype: Metric :raises TypeError: if an argument's type differs from the expected type :raises UnknownTypeException: if a type argument fails to parse :raises OpenDPException: packaged error from the core OpenDP library """ # No type arguments to standardize. # Convert arguments to c types. c_this = py_to_c(this, c_type=Transformation, type_name=None) # Call library function. lib_function = lib.opendp_core__transformation_output_metric lib_function.argtypes = [Transformation] lib_function.restype = FfiResult output = unwrap(lib_function(c_this), Metric) return output