code: def info(self):
          
          itext = self.class_info
          if self.key_prop.info and self.value_prop.info:
              itext += ' (keys: {}; values: {})'.format(
                  self.key_prop.info, self.value_prop.info
              )
          elif self.key_prop.info:
              itext += ' (keys: {})'.format(self.key_prop.info)
          elif self.value_prop.info:
              itext += ' (values: {})'.format(self.value_prop.info)
          return itext
docs: Supplemental description of the list, with length and type