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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def empowerment(iface, priority=0):
 """ Class decorator for indicating a powerup's powerup interfaces. The class will also be declared as implementing the interface. @type iface: L{zope.interface.Interface} @param iface: The powerup interface. @type priority: int @param priority: The priority the powerup will be installed at. """

    def _deco(cls):
        cls.powerupInterfaces = (
            tuple(getattr(cls, 'powerupInterfaces', ())) +
            ((iface, priority),))
        implementer(iface)(cls)
        return cls
    return _deco