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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:
 """All subclasses of a class. From: http://stackoverflow.com/a/17246726/2692780 """

    subclasses = []
    for subclass in cls.__subclasses__():
        subclasses.append(subclass)
        subclasses.extend(all_subclasses(subclass))
    return tuple(subclasses)