def test_extraChainDoesNotBreakPyOpenSSL(self):
        """
        C{extraCertChain} doesn't break C{OpenSSL.SSL.Context} creation.
        """
        opts = sslverify.OpenSSLCertificateOptions(
            privateKey=self.sKey,
            certificate=self.sCert,
            extraCertChain=self.extraCertChain,
        )
        ctx = opts.getContext()
        self.assertIsInstance(ctx, SSL.Context)

        C{extraCertChain} doesn't break C{OpenSSL.SSL.Context} creation.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_sslverify.py