for attr_name, attr_obj in self._attrs.iteritems():
attr_value = self.get(attr_name)
- if attr_value is not None and attr_obj.flags == 8 and \
+ if attr_value is not None and attr_obj.has_flag(Flags.Filter) and \
attr_name != 'timeframe':
attr_tag = attr_to_tags[attr_name]