'Verify tls-sni-01 challenge certificate.
:param OpensSSL.crypto.X509 cert: Challenge certificate.
:returns: Whether the certificate was successfully verified.
:rtype: bool'

def verify_cert(self, cert):

    sans = crypto_util._pyopenssl_cert_or_req_san(cert)
    logger.debug('Certificate    %s.    SANs:    %s', cert.digest('sha256'), sans)
    return (self.z_domain.decode() in sans)
