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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 save_binary(self, filename):
 """Save Dataset to a binary file. Parameters filename : string Name of the output file. Returns ------- self : Dataset Returns self. """

        _safe_call(_LIB.LGBM_DatasetSaveBinary(
            self.construct().handle,
            c_str(filename)))
        return self