def get_repository_notification_session(self, repository_receiver, proxy):
if repository_receiver is None:<EOL><INDENT>raise NullArgument()<EOL><DEDENT>if not self.supports_repository_notification():<EOL><INDENT>raise Unimplemented()<EOL><DEDENT>try:<EOL><INDENT>from . import sessions<EOL><DEDENT>except ImportError:<EOL><INDENT>raise  <EOL><DEDENT>proxy = self._convert_proxy(proxy)<EOL>try:<EOL><INDENT>session = sessions.RepositoryNotificationSession(repository_receiver, proxy, runtime=self._runtime)<EOL><DEDENT>except AttributeError:<EOL><INDENT>raise  <EOL><DEDENT>return session<EOL>
Gets the notification session for subscribing to changes to a
        repository.

        arg:    repository_receiver
                (osid.repository.RepositoryReceiver): the notification
                callback
        arg     proxy (osid.proxy.Proxy): a proxy
        return: (osid.repository.RepositoryNotificationSession) - a
                RepositoryNotificationSession
        raise:  NullArgument - repository_receiver is null
        raise:  OperationFailed - unable to complete request
        raise:  Unimplemented - supports_repository_notification() is
                false
        compliance: optional - This method must be implemented if
                    supports_repository_notification() is true.