class ShortcutManager:
    def __init__(self):
        self._handlers = {}

    def register(self, hotkey: str, callback):
        self._handlers[hotkey.lower()] = callback

    def trigger(self, hotkey: str):
        cb = self._handlers.get(hotkey.lower())
        if cb:
            return cb()
        return None

    def list(self):
        return dict(self._handlers)
