def newMessages(exists, recent):
        """
        Indicates that the number of messages in a mailbox has changed.

        @type exists: L{int} or L{None}
        @param exists: The total number of messages now in this mailbox. If the
            total number of messages has not changed, this should be L{None}.

        @type recent: L{int}
        @param recent: The number of messages now flagged C{\\Recent}. If the
            number of recent messages has not changed, this should be L{None}.
        """

        Indicates that the number of messages in a mailbox has changed.

        @type exists: L{int} or L{None}
        @param exists: The total number of messages now in this mailbox. If the
            total number of messages has not changed, this should be L{None}.

        @type recent: L{int}
        @param recent: The number of messages now flagged C{\Recent}. If the
            number of recent messages has not changed, this should be L{None}.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/mail/interfaces.py