def _register_server_authenticator(klass, name):
<EOL>SERVER_MECHANISMS_D[name] = klass<EOL>items = sorted(SERVER_MECHANISMS_D.items(), key = _key_func, reverse = True)<EOL>SERVER_MECHANISMS[:] = [k for (k, v) in items ]<EOL>SECURE_SERVER_MECHANISMS[:] = [k for (k, v) in items<EOL>if v._pyxmpp_sasl_secure]<EOL>
Add a client authenticator class to `SERVER_MECHANISMS_D`,
    `SERVER_MECHANISMS` and, optionally, to `SECURE_SERVER_MECHANISMS`