message: Add mask keyword to ensure that we don't pass masks in place of training.
diff: @@ -396,7 +396,7 @@ class Network(base_layer.Layer):
  if cache_key in self._output_mask_cache:
  return self._output_mask_cache[cache_key]
  else:
  - _, output_masks = self._run_internal_graph(inputs, masks)
  + _, output_masks = self._run_internal_graph(inputs, mask=masks)
  return output_masks
  @property
  