message: Update core.py
  Added `data_format` to flatten to allow changing of it during inference time.
diff: @@ -269,6 +269,13 @@ def dropout(inputs,
  class Flatten(keras_layers.Flatten, base.Layer):
  """Flattens an input tensor while preserving the batch axis (axis 0).
  + Arguments:
  + data_format: A string, one of `channels_last` (default) or `channels_first`.
  + The ordering of the dimensions in the inputs.
  + `channels_last` corresponds to inputs with shape
  + `(batch, ..., channels)` while `channels_first` corresponds to
  + inputs with shape `(batch, channels, ...)`.
  +
  Examples:
  ```
  @@ -285,11 +292,16 @@ class Flatten(keras_layers.Flatten, base.Layer):
  @tf_export('layers.flatten')
  -def flatten(inputs, name=None):
  +def flatten(inputs, data_format='channels_last', name=None):
  """Flattens an input tensor while preserving the batch axis (axis 0).
  Arguments:
  inputs: Tensor input.
  + data_format: A string, one of `channels_last` (default) or `channels_first`.
  + The ordering of the dimensions in the inputs.
  + `channels_last` corresponds to inputs with shape
  + `(batch, height, width, channels)` while `channels_first` corresponds to
  + inputs with shape `(batch, channels, height, width)`.
  name: The name of the layer (string).
  Returns:
  @@ -307,7 +319,7 @@ def flatten(inputs, name=None):
  # now `y` has shape `(None, None)`
  ```
  """
  - layer = Flatten(name=name)
  + layer = Flatten(data_format=data_format, name=name)
  return layer.apply(inputs)
  