code: def set_description(self, description, lang=None):
          
          description = Validation.description_check_convert(description)
          lang = Validation.lang_check_convert(lang, default=self._default_lang)
          # remove any other descriptions with this language before adding
          self.delete_description(lang)
          subj = self._get_uuid_uriref()
          self._graph.add((subj, self._commentPredicate, Literal(description, lang)))
docs: Sets the `description` metadata property on your Thing/Point.  Only one description is allowed per language,
          so any other descriptions in this language are removed before adding this one
  
          Raises `ValueError` containing an error message if the parameters fail validation
  
          `description` (mandatory) (string) the new text of the description
  
          `lang` (optional) (string) The two-character ISO 639-1 language code to use for your label.
          None means use the default language for your agent.
          See [Config](./Config.m.html#IoticAgent.IOT.Config.Config.__init__)