def test_privateBlobEC(self):
        """
        L{keys.Key.privateBlob} returns the SSH ptotocol-level format of EC
        private key.
        """
        self.assertEqual(
            keys.Key(self.ecObj).privateBlob(),
            common.NS(keydata.ECDatanistp256['curve']) +
            common.MP(self.ecObj.private_numbers().public_numbers.x) +
            common.MP(self.ecObj.private_numbers().public_numbers.y) +
            common.MP(self.ecObj.private_numbers().private_value)
            )

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