message: Try hashing first in _make_input_signature_hashable
diff: @@ -105,9 +105,17 @@ def _make_input_signature_hashable(elem):
  Returns:
  A hashable object for the requested input signature
  """
  + try:
  + hash(elem)
  + except TypeError:
  + return _make_input_signature_hashable_helper(elem)
  + return elem
  +
  +
  +def _make_input_signature_hashable_helper(elem):
  # TODO(slebedev): consider using nest.
  if isinstance(elem, tuple):
  - return tuple(map(_make_input_signature_hashable, elem))
  + return tuple(map(_make_input_signature_hashable_helper, elem))
  try:
  hash(elem)
  