code: def msg_filter(self):
          
          if self.query:
              msg_filter = None
          else:
              msg_filter = self._request_request('msg_filter', 'all')
              available_msg_filters = {'untranslated', 'translated', 'fuzzy', 'all'}
              if msg_filter not in available_msg_filters:
                  msg_filter = 'all'
          return msg_filter
docs: Validate/return msg_filter from request (e.g. 'fuzzy', 'untranslated'),
          or a default.
  
          If a query is also specified in the request, then return None.