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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 document(cls):
 """ Decorator to document a class """

    if cls.__doc__ is None:
        return cls

    baseclass_name = cls.mro()[-2].__name__

    try:
        return DOC_FUNCTIONS[baseclass_name](cls)
    except KeyError:
        return cls