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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 split(self, frac):
 """ Split the DataFrame into two DataFrames with certain ratio. :param frac: Split ratio :type frac: float :return: two split DataFrame objects :rtype: list[DataFrame] """

        from .. import preprocess
        split_obj = getattr(preprocess, '_Split')(fraction=frac)
        return split_obj.transform(self)