code: def tr(self, subdomain: str, string_to_translate: str = "") -> str:
          
          if subdomain not in self.translations.keys():
              raise ValueError(
                  "'{}' is not a correct subdomain."
                  " Must be one of {}".format(subdomain, self.translations.keys())
              )
          else:
              pass
          # translate
          str_translated = self.translations.get(
              subdomain, {"error": "Subdomain not found: {}".format(subdomain)}
          ).get(string_to_translate, "String not found")
  
          # end of method
          return str_translated
docs: Returns translation of string passed.
  
          :param str subdomain: subpart of strings dictionary.
           Must be one of self.translations.keys() i.e. 'restrictions'
          :param str string_to_translate: string you want to translate