def _unblock(self, _):
        """
        Process as many blocked commands as possible.

        If there are no more blocked commands, set up for the next command to
        be sent immediately.

        @type _: L{object}
        @param _: Ignored.
        """
        commands = self.blocked
        self.blocked = None
        while commands and self.blocked is None:
            cmd, args = commands.pop(0)
            self.processCommand(cmd, *args)
        if self.blocked is not None:
            self.blocked.extend(commands)

        Process as many blocked commands as possible.

        If there are no more blocked commands, set up for the next command to
        be sent immediately.

        @type _: L{object}
        @param _: Ignored.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/mail/pop3.py