docs: def query(self):
          """A QueryDict object holding the query parameters (QUERY_STRING)."""
          if self._query is None:
              query_string = self.environ.get('QUERY_STRING')
              self._query = QueryDict([
                  (k.decode('utf-8'), v.decode('utf-8'))
                  for k, v in urlparse.parse_qsl(
                      query_string, keep_blank_values=True)
              ])
          return self._query