def _parse_ssl_options(options):
    """Parse ssl options."""
    use_ssl = options.get('ssl')
    if use_ssl is not None:
        validate_boolean('ssl', use_ssl)

    certfile = options.get('ssl_certfile')
    keyfile = options.get('ssl_keyfile')
    passphrase = options.get('ssl_pem_passphrase')
    ca_certs = options.get('ssl_ca_certs')
    cert_reqs = options.get('ssl_cert_reqs')
    match_hostname = options.get('ssl_match_hostname', True)
    crlfile = options.get('ssl_crlfile')

    ssl_kwarg_keys = [k for k in options
                      if k.startswith('ssl_') and options[k]]
    if use_ssl == False and ssl_kwarg_keys:
        raise ConfigurationError("ssl has not been enabled but the "
                                 "following ssl parameters have been set: "
                                 "%s. Please set `ssl=True` or remove."
                                 % ', '.join(ssl_kwarg_keys))

    if ssl_kwarg_keys and use_ssl is None:
        # ssl options imply ssl = True
        use_ssl = True

    if use_ssl is True:
        ctx = get_ssl_context(
            certfile,
            keyfile,
            passphrase,
            ca_certs,
            cert_reqs,
            crlfile,
            match_hostname)
        return ctx, match_hostname
    return None, match_hostname
Parse ssl options.