Create HParams with data_dir and problem hparams, if kwargs provided.

def create_hparams(hparams_set,
                   hparams_overrides_str="",
                   data_dir=None,
                   problem_name=None,
                   hparams_path=None):
  """Create HParams with data_dir and problem hparams, if kwargs provided."""
  hparams = registry.hparams(hparams_set)
  if hparams_path and tf.gfile.Exists(hparams_path):
    hparams = create_hparams_from_json(hparams_path, hparams)
  if data_dir:
    hparams.add_hparam("data_dir", data_dir)
  if hparams_overrides_str:
    tf.logging.info("Overriding hparams in %s with %s", hparams_set,
                    hparams_overrides_str)
    hparams = hparams.parse(hparams_overrides_str)
  if problem_name:
    add_problem_hparams(hparams, problem_name)
  return hparams