code: def _generate_union_class_get_helpers(self, ns, data_type):
          # type: (ApiNamespace, Union) -> None
          
          for field in data_type.fields:
              field_name = fmt_func(field.name)
  
              if not is_void_type(field.data_type):
                  # generate getter for field
                  val_type = self.map_stone_type_to_pep484_type(ns, field.data_type)
  
                  self.emit('def get_{field_name}(self) -> {val_type}: ...'.format(
                      field_name=field_name,
                      val_type=val_type,
                  ))
                  self.emit()
docs: Generates the following section in the 'union Shape' example:
          def get_circle(self) -> float: ...