def _cbSignedData(self, signedData):
        """
        Called back out of self.signData with the signed data.  Send the
        authentication request with the signature.

        @param signedData: the data signed by the user's private key.
        @type signedData: L{bytes}
        """
        publicKey = self.lastPublicKey
        self.askForAuth(b'publickey', b'\x01' + NS(publicKey.sshType()) +
                NS(publicKey.blob()) + NS(signedData))

        Called back out of self.signData with the signed data.  Send the
        authentication request with the signature.

        @param signedData: the data signed by the user's private key.
        @type signedData: L{bytes}
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/conch/ssh/userauth.py