message: Update nested_structure_coder.py
diff: @@ -217,7 +217,7 @@ class _NamedTupleCodec(object):
  """Codec for namedtuples.
  Encoding and decoding a namedtuple reconstructs a namedtuple with a different
  - actual Python type, but with same `typename` and `fields`.
  + actual Python type, but with the same `typename` and `fields`.
  """
  def can_encode(self, pyobj):
  