def close():
        """
        Close this mailbox.

        @return: A L{Deferred} which fires when this mailbox has been closed,
            or None if the mailbox can be closed immediately.
        """

        Close this mailbox.

        @return: A L{Deferred} which fires when this mailbox has been closed,
            or None if the mailbox can be closed immediately.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/mail/interfaces.py