<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def register_auth_method(self, auth_method):
 """ Register a new authentication method name the name of the authentication method, typically displayed by the webapp input_to_display Only available after that the Plugin Manager is loaded """

        if not self._loaded:
            raise PluginManagerNotLoadedException()
        self._user_manager.register_auth_method(auth_method)