code: def show_options(self, key=""):
          
          key, _ = _lower_keys(key, '')
  
          if key == "":
              return self.gc.copy()
          return self.gc[(self.gc["k1"] == key)].copy()
docs: Returns a copy the options :class:`~pandas.DataFrame`.
  
          Called on jupyter notebook, it will print them in pretty
          :class:`~pandas.DataFrame` format.
  
          :param str key: First identifier of the option. If not provided,
              all options are returned.
  
          :return: :class:`~pandas.DataFrame`