def test_privateBlobRSA(self):
        """
        L{keys.Key.privateBlob} returns the SSH protocol-level format of an
        RSA private key.
        """
        from cryptography.hazmat.primitives.asymmetric import rsa
        numbers = self.rsaObj.private_numbers()
        u = rsa.rsa_crt_iqmp(numbers.q, numbers.p)
        self.assertEqual(
            keys.Key(self.rsaObj).privateBlob(),
            common.NS(b'ssh-rsa') +
            common.MP(self.rsaObj.private_numbers().public_numbers.n) +
            common.MP(self.rsaObj.private_numbers().public_numbers.e) +
            common.MP(self.rsaObj.private_numbers().d) +
            common.MP(u) +
            common.MP(self.rsaObj.private_numbers().p) +
            common.MP(self.rsaObj.private_numbers().q)
            )

        L{keys.Key.privateBlob} returns the SSH protocol-level format of an
        RSA private key.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/conch/test/test_keys.py