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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 _superdir(self):
 """ Return a list of slots and methods, including those from subclasses. """

        attrs = set()
        cls = self.__class__
        if hasattr(cls, '__all_slots__'):
            attrs.update(cls.__all_slots__)
        for bcls in cls.__mro__:
            if hasattr(bcls, '__dict__'):
                attrs.update(bcls.__dict__)
        return attrs