def test_constructorDoesNotAllowVerifyWithoutCACerts(self):
        """
        C{verify} must not be C{True} without specifying C{caCerts}.
        """
        self.assertRaises(
            ValueError,
            sslverify.OpenSSLCertificateOptions,
            privateKey=self.sKey, certificate=self.sCert, verify=True
        )

        C{verify} must not be C{True} without specifying C{caCerts}.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_sslverify.py