code: def dump_text(self, filename):
          
          _safe_call(_LIB.LGBM_DatasetDumpText(
              self.construct().handle,
              c_str(filename)))
          return self
docs: 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.