code: def to_rst_(self) -> str:
          
          try:
              renderer = pytablewriter.RstGridTableWriter
              data = self._build_export(renderer)
              return data
          except Exception as e:
              self.err(e, "Can not convert data to restructured text")
docs: Convert the main dataframe to restructured text
  
          :return: rst data
          :rtype: str
  
          :example: ``ds.to_rst_()``