def _SetOrderAttrs(self):
    if self._order is None:
      return

    unclean_attr_names = self._order.strip().split(',')
    result = []
    for attr_name in unclean_attr_names:
      ascending = True
      if attr_name.startswith('-'):
        ascending = False
        attr_name = attr_name[1:]

      attr = self._entity._properties.get(attr_name)
      if attr is None:
        raise AttributeError('Order attribute %s not defined.' % (attr_name,))

      if ascending:
        result.append(+attr)
      else:
        result.append(-attr)

    self._order_attrs = tuple(result)
convert given value list to AllowedValue objects
dataset/ETHPy150Open GoogleDeveloperExperts/experts-app-backend/endpoints_proto_datastore/ndb/model.py/_EndpointsQueryInfo._SetOrderAttrs--crossover with--dataset/ETHPy150Open geopython/pywps/pywps/inout/literaltypes.py/make_allowedvalues