from abc import ABC, abstractmethod

_handled_signals = {}

def _signal_handler(signal, frame):
    if not signal in _handled_signals.keys():
        return
    for h in _handled_signals[signal]:
        h.func(signal, *h.args)

class Signals:

    class Handler:
        def __init__(self, func, args):
            self.func = func
            self.args = args

    def __init(self):
        pass

    @classmethod
    @abstractmethod
    def _add_handler(self, signal, handler):
        raise Exception("_add_handler() is not reimplemented")

    @classmethod
    def add_handler(cls, signals, handler, *args):
        for signal in signals:
            h = Signals.Handler(handler, args)
            if not signal in _handled_signals.keys():
                _handled_signals[signal] = [h]
                cls._add_signal_handler(signal, _signal_handler)
            else:
                _handled_signals[signal].add(h)