code: def delete_label(self, lang=None):
          
          self._remove_properties_by_language(self._labelPredicate,
                                              Validation.lang_check_convert(lang, default=self._default_lang))
docs: Deletes all the `label` metadata properties on your Thing/Point for this language
  
          Raises `ValueError` containing an error message if the parameters fail validation
  
          `lang` (optional) (string) The two-character ISO 639-1 language code to identify your label.
          None means use the default language for your agent.
          See [Config](./Config.m.html#IoticAgent.IOT.Config.Config.__init__)