gistfile1.py

# before
    # In plugin manager:
    def register_trigger(self, func, *events):
        for event in events:
            self.triggers[event.upper()].append(func)

    # In plugin:
    def initialize(self, *args, **kwargs):
        manager.register_trigger(self.on_welcome, "IRC_RPL_WELCOME")

    def on_welcome(self, bot, command, prefix, params):
        ...

# now
    # In plugin manager        
    def trigger(self, event):
        def process(func):
            for event in events:
                self.triggers[event.upper()].append(func)
            return func
        return process
    
    # In plugin:
    @manager.trigger("IRC_RPL_WELCOME")
    def on_welcome(self, bot, command, prefix, params):
        ...