def close():
        """
        Perform any post-write work that needs to be done. This method may
        only be invoked once on each provider, and will always be invoked
        after receive().

        @rtype: C{Deferred} of anything: the value is ignored. The FTP client
        will not see their upload request complete until this Deferred has
        been fired.
        """

        Perform any post-write work that needs to be done. This method may
        only be invoked once on each provider, and will always be invoked
        after receive().

        @rtype: C{Deferred} of anything: the value is ignored. The FTP client
        will not see their upload request complete until this Deferred has
        been fired.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/protocols/ftp.py