text: # Copyright 2019 The TensorFlow Authors. All Rights Reserved.
  #
  # 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.
  # ==============================================================================
  """Abstract Base Class for quantization transformations to a keras model.
  
  Keras models need certain transformations for quantization to exactly match the
  behavior of the backend they will be implemented on. This is important for
  improving model performance.
  
  This interface abstracts that behavior. Different backends can implement their
  own version.
  
  Module: tfmot.quantization.keras
  """
  
  from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  
  import abc
  import six
  
  
  @six.add_metaclass(abc.ABCMeta)
  class QuantizeLayoutTransform(object):
    """Apply transformations to the model.
  
    Transforms the original model to perform better while quantized
    and also match the layout of the target backend.
    """
  
    @abc.abstractmethod
    def apply(self, model):
      """Transform model to a quantization friendly model.
  
      Args:
        model: Keras model to be quantized.
  
      Returns:
        New keras model based on `model` which has been
        transformed to match the layout of the target backend.
      """
      raise NotImplementedError('Must be implemented in subclasses.')
  