def reset(self):
        """
        Instruct the target to forget any related exception.
        """
        if not self.chain_id:
            return

        saved, self.chain_id = self.chain_id, None
        try:
            self.call_no_reply(mitogen.core.Dispatcher.forget_chain, saved)
        finally:
            self.chain_id = saved
Instruct the target to forget any related exception.