code: def get_details(self):
          
          strval = str(self.wrong_value)
          if len(strval) > self.__max_str_length_displayed__:
              return '(Actual value is too big to be printed in this message)'
          else:
              return 'Wrong value: [{}]'.format(self.wrong_value)
docs: The function called to get the details appended to the help message when self.append_details is True