docs: def _get_serialize_func(self, name, spec):
          """ Return the function that is used for serialization. """
          func = getattr(self, 'serialize_' + name, None)
          if func:
              # this factory has a special serializer function for this field
              return func
          func = getattr(spec.fields[name], 'serialize', None)
          if func:
              return func
          return lambda value, entity, request: value