def getPublicKey(self):
        """
        If this is the first time we've been called, return a blob for
        the DSA key.  Otherwise, return a blob
        for the RSA key.
        """
        if self.lastPublicKey:
            return keys.Key.fromString(keydata.publicRSA_openssh)
        else:
            return defer.succeed(
                keys.Key.fromString(keydata.publicDSA_openssh))

        If this is the first time we've been called, return a blob for
        the DSA key.  Otherwise, return a blob
        for the RSA key.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/conch/test/test_userauth.py