Build the base query dictionary

def _build_query(self):
        """
        Build the base query dictionary
        """
        if isinstance(self._query_string, QueryString):
            self._query_dsl = self._query_string
        elif isinstance(self._query_string, string_types):
            self._query_dsl = QueryString(self._query_string)
        else:
            self._query_dsl = MatchAll()