def remote_loginAnonymous(self, mind):
        """
        Attempt an anonymous login.

        @param mind: An object to use as the mind parameter to the portal login
            call (possibly None).

        @rtype: L{Deferred}
        @return: A Deferred which will be called back with an avatar when login
            succeeds or which will be errbacked if login fails somehow.
        """
        d = self.portal.login(Anonymous(), mind, IPerspective)
        d.addCallback(self._cbLogin)
        return d

        Attempt an anonymous login.

        @param mind: An object to use as the mind parameter to the portal login
            call (possibly None).

        @rtype: L{Deferred}
        @return: A Deferred which will be called back with an avatar when login
            succeeds or which will be errbacked if login fails somehow.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/spread/pb.py