docs: def to_api(self):
          """Return a dictionary to send to the API.
  
          Returns:
              dict: Mapping representing this object that can be sent to the
               API.
          """
          vals = {}
          for attribute, attribute_type in self._props.items():
              prop = getattr(self, attribute)
              vals[self._to_camel_case(attribute)] = self._to_api_value(
                  attribute_type, prop,
              )
          return vals