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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def lock(self, session):
 """Lock the connection, ensuring that it is not busy and storing a weakref for the session. :param queries.Session session: The session to lock the connection with :raises: ConnectionBusyError """

        if self.busy:
            raise ConnectionBusyError(self)
        with self._lock:
            self.used_by = weakref.ref(session)
        LOGGER.debug('Connection %s locked', self.id)