def _close(self):
        """Close the tough connection.

        You can always close a tough connection with this method
        and it will not complain if you close it more than once.

        """
        if not self._closed:
            try:
                self._con.close()
            except Exception:
                pass
            self._transaction = False
            self._closed = True
Close the tough connection.

        You can always close a tough connection with this method
        and it will not complain if you close it more than once.