old_contents: # Copyright 2020, The TensorFlow Federated Authors.
  #
  # Licensed under the Apache License, Version 2.0 (the "License");
  # you may not use this file except in compliance with the License.
  # You may obtain a copy of the License at
  #
  #      http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS,
  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  # See the License for the specific language governing permissions and
  # limitations under the License.
  """A library of contruction functions for computation structures."""
  
  from tensorflow_federated.proto.v0 import computation_pb2 as pb
  from tensorflow_federated.python.core.api import computation_types
  from tensorflow_federated.python.core.impl.types import type_factory
  from tensorflow_federated.python.core.impl.types import type_serialization
  
  
  def create_lambda_empty_tuple() -> pb.Computation:
    """Returns a lambda computation returning an empty tuple.
  
    Has the type signature:
  
    ( -> <>)
  
    Returns:
      An instance of `pb.Computation`.
    """
    result_type = computation_types.NamedTupleType([])
    type_signature = computation_types.FunctionType(None, result_type)
    result = pb.Computation(
        type=type_serialization.serialize_type(result_type),
        tuple=pb.Tuple(element=[]))
    fn = pb.Lambda(parameter_name=None, result=result)
    # We are unpacking the lambda argument here because `lambda` is a reserved
    # keyword in Python, but it is also the name of the parameter for a
    # `pb.Computation`.
    # https://developers.google.com/protocol-buffers/docs/reference/python-generated#keyword-conflicts
    return pb.Computation(
        type=type_serialization.serialize_type(type_signature), **{'lambda': fn})  # pytype: disable=wrong-keyword-args
  
  
  def create_lambda_identity(type_spec) -> pb.Computation:
    """Returns a lambda computation representing an identity function.
  
    Has the type signature:
  
    (T -> T)
  
    Args:
      type_spec: A type convertible to instance of `computation_types.Type` via
        `computation_types.to_type`.
  
    Returns:
      An instance of `pb.Computation`.
    """
    type_spec = computation_types.to_type(type_spec)
    type_signature = type_factory.unary_op(type_spec)
    result = pb.Computation(
        type=type_serialization.serialize_type(type_spec),
        reference=pb.Reference(name='a'))
    fn = pb.Lambda(parameter_name='a', result=result)
    # We are unpacking the lambda argument here because `lambda` is a reserved
    # keyword in Python, but it is also the name of the parameter for a
    # `pb.Computation`.
    # https://developers.google.com/protocol-buffers/docs/reference/python-generated#keyword-conflicts
    return pb.Computation(
        type=type_serialization.serialize_type(type_signature), **{'lambda': fn})  # pytype: disable=wrong-keyword-args
  
new_contents: # Copyright 2020, The TensorFlow Federated Authors.
  #
  # Licensed under the Apache License, Version 2.0 (the "License");
  # you may not use this file except in compliance with the License.
  # You may obtain a copy of the License at
  #
  #      http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS,
  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  # See the License for the specific language governing permissions and
  # limitations under the License.
  """A library of contruction functions for computation structures."""
  
  from tensorflow_federated.proto.v0 import computation_pb2 as pb
  from tensorflow_federated.python.core.api import computation_types
  from tensorflow_federated.python.core.impl.types import type_factory
  from tensorflow_federated.python.core.impl.types import type_serialization
  
  
  def create_lambda_empty_tuple() -> pb.Computation:
    """Returns a lambda computation returning an empty tuple.
  
    Has the type signature:
  
    ( -> <>)
  
    Returns:
      An instance of `pb.Computation`.
    """
    result_type = computation_types.NamedTupleType([])
    type_signature = computation_types.FunctionType(None, result_type)
    result = pb.Computation(
        type=type_serialization.serialize_type(result_type),
        tuple=pb.Tuple(element=[]))
    fn = pb.Lambda(parameter_name=None, result=result)
    # We are unpacking the lambda argument here because `lambda` is a reserved
    # keyword in Python, but it is also the name of the parameter for a
    # `pb.Computation`.
    # https://developers.google.com/protocol-buffers/docs/reference/python-generated#keyword-conflicts
    return pb.Computation(
        type=type_serialization.serialize_type(type_signature), **{'lambda': fn})  # pytype: disable=wrong-keyword-args
  
  
  def create_lambda_identity(type_spec: computation_types.Type) -> pb.Computation:
    """Returns a lambda computation representing an identity function.
  
    Has the type signature:
  
    (T -> T)
  
    Args:
      type_spec: A `computation_types.Type`.
  
    Returns:
      An instance of `pb.Computation`.
    """
    type_signature = type_factory.unary_op(type_spec)
    result = pb.Computation(
        type=type_serialization.serialize_type(type_spec),
        reference=pb.Reference(name='a'))
    fn = pb.Lambda(parameter_name='a', result=result)
    # We are unpacking the lambda argument here because `lambda` is a reserved
    # keyword in Python, but it is also the name of the parameter for a
    # `pb.Computation`.
    # https://developers.google.com/protocol-buffers/docs/reference/python-generated#keyword-conflicts
    return pb.Computation(
        type=type_serialization.serialize_type(type_signature), **{'lambda': fn})  # pytype: disable=wrong-keyword-args
  
subject: Remove usage of `computation_type.to_type` from `computation_factory`.