def test_signDataDSA(self):
        """
        Sign data with a DSA private key and then verify it with the public
        key.
        """
        d = self.client.signData(self.dsaPublic.blob(), b"John Hancock")
        self.pump.flush()
        def _check(sig):
            # Cannot do this b/c DSA uses random numbers when signing
            #   expected = self.dsaPrivate.sign("John Hancock")
            #   self.assertEqual(expected, sig)
            self.assertTrue(self.dsaPublic.verify(sig, b"John Hancock"))
        return d.addCallback(_check)

        Sign data with a DSA private key and then verify it with the public
        key.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/conch/test/test_agent.py