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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 dump_text(self, filename):
 """Save Dataset to a text file. This format cannot be loaded back in by LightGBM, but is useful for debugging purposes. Parameters filename : string Name of the output file. Returns ------- self : Dataset Returns self. """

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