code: def truck(self, model_mask: str = '#### @@') -> str:
          
          return '{}-{}'.format(
              self.random.choice(TRUCKS),
              self.random.custom_code(model_mask),
          )
docs: Generate a truck model.
  
          :param model_mask: Mask of truck model. Here '@' is a
              placeholder of characters and '#' is a placeholder of digits.
          :return: Dummy truck model.
  
          :Example:
              Caledon-966O.