message: Simplify _should_unpack_args()
diff: @@ -1903,8 +1903,7 @@ class DenseToSparseBatchDataset(Dataset):
  def _should_unpack_args(args):
  """Returns `True` if `args` should be `*args` when passed to a callable."""
  - is_namedtuple = isinstance(args, tuple) and hasattr(args, "_fields")
  - return nest.is_sequence(args) and not isinstance(args, dict) and not is_namedtuple
  + return type(args) is tuple # pylint: disable=unidiomatic-typecheck
  class _ResourceDataset(Dataset):
  