<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_handler(self, target=None):
 """Decorator for a function to be used as a signal handler. :param str|unicode target: Where this signal will be delivered to. Default: ``worker``. * ``workers`` - run the signal handler on all the workers * ``workerN`` - run the signal handler only on worker N * ``worker``/``worker0`` - run the signal handler on the first available worker * ``active-workers`` - run the signal handlers on all the active [non-cheaped] workers * ``mules`` - run the signal handler on all of the mules * ``muleN`` - run the signal handler on mule N * ``mule``/``mule0`` - run the signal handler on the first available mule * ``spooler`` - run the signal on the first available spooler * ``farmN/farm_XXX`` - run the signal handler in the mule farm N or named XXX * http://uwsgi.readthedocs.io/en/latest/Signals.html#signals-targets """

        target = target or 'worker'
        sign_num = self.num

        def wrapper(func):

            _LOG.debug("Registering '%s' as signal '%s' handler ...", func.__name__, sign_num)

            uwsgi.register_signal(sign_num, target, func)

            return func

        return wrapper