old_contents: import typing as tp  # NOQA
  
  from chainer import types  # NOQA
  from chainer import utils
  
  
  class Initializer(object):
      """Initializes array.
  
      It initializes the given array.
  
      Attributes:
          dtype: Data type specifier. It is for type check in ``__call__``
              function.
  
      """
  
      def __init__(self, dtype=None):
          # type: (tp.Optional[types.DTypeSpec]) -> None
  
          self.dtype = dtype  # type: types.DTypeSpec
  
      def __call__(self, array):
          # type: (types.NdArray) -> None
          """Initializes given array.
  
          This method destructively changes the value of array.
          The derived class is required to implement this method.
          The algorithms used to make the new values depend on the
          concrete derived classes.
  
          Args:
              array (:ref:`ndarray`):
                  An array to be initialized by this initializer.
  
          """
          raise NotImplementedError()
  
  
  # Original code forked from MIT licensed keras project
  # https://github.com/fchollet/keras/blob/master/keras/initializations.py
  
  def get_fans(shape):
      if not isinstance(shape, tuple):
          raise ValueError('shape must be tuple')
  
      if len(shape) < 2:
          raise ValueError('shape must be of length >= 2: shape={}', shape)
  
      receptive_field_size = utils.size_of_shape(shape[2:])
      fan_in = shape[1] * receptive_field_size
      fan_out = shape[0] * receptive_field_size
      return fan_in, fan_out
  
new_contents: import typing as tp  # NOQA
  
  from chainer import types  # NOQA
  from chainer import utils
  
  
  class Initializer(object):
      """Initializes array.
  
      It initializes the given array.
  
      Attributes:
          dtype: Data type specifier. It is for type check in ``__call__``
              function.
  
      """
  
      def __init__(self, dtype=None):
          # type: (tp.Optional[types.DTypeSpec]) -> None
  
          self.dtype = dtype  # type: types.DTypeSpec
  
      def __call__(self, array):
          # type: (types.NdArray) -> None
          """Initializes given array.
  
          This method destructively changes the value of array.
          The derived class is required to implement this method.
          The algorithms used to make the new values depend on the
          concrete derived classes.
  
          Args:
              array (:ref:`ndarray`):
                  An array to be initialized by this initializer.
  
          """
          raise NotImplementedError()
  
  
  # Original code forked from MIT licensed keras project
  # https://github.com/fchollet/keras/blob/master/keras/initializations.py
  
  def get_fans(shape):
      if not isinstance(shape, tuple):
          raise ValueError(
              'shape must be tuple. Actual type: {}'.format(type(shape)))
  
      if len(shape) < 2:
          raise ValueError(
              'shape must be of length >= 2. Actual shape: {}'.format(shape))
  
      receptive_field_size = utils.size_of_shape(shape[2:])
      fan_in = shape[1] * receptive_field_size
      fan_out = shape[0] * receptive_field_size
      return fan_in, fan_out
  
subject: Fix error messages in get_fans