Extracts and returns the serialized object.

def payload(self):
    """Extracts and returns the serialized object."""
    try:
      rdf_cls = self.classes.get(self.name)
      if rdf_cls:
        value = rdf_cls.FromSerializedString(self.data)
        value.age = self.embedded_age

        return value
    except TypeError:
      return None