// A concrete function's serialized "canonicalized_input_signature" comes
  // from encoding its "structured_input_signature" field:
  // https://github.com/tensorflow/tensorflow/blob/1c064ab76064c58e54261b805027474885a1534d/tensorflow/python/saved_model/function_serialization.py#L70-L71
  // The "structured_input_signature" is guaranteed to be a tuple of the python
  // args, kwargs that correspond to the tf.function:

      input keys and input values of the representative samples should match the
      keyword arguments of `func`.
  """
  _, keyword_args = func.structured_input_signature
  sample_validator = _create_sample_validator(
      expected_input_keys=keyword_args.keys()
  )

  for sample in map(
      sample_validator, _log_sample_num_for_calibration(representative_dataset)