Gets a cursor, executes `stmt` and closes the cursor,
        fetching one row afterwards and returning its result.

def _execute(self, stmt, *values):
        """
        Gets a cursor, executes `stmt` and closes the cursor,
        fetching one row afterwards and returning its result.
        """
        c = self._cursor()
        try:
            return c.execute(stmt, values).fetchone()
        finally:
            c.close()