code: def add_showanswer(self, showanswer):
          
          if showanswer is None:
              raise NullArgument('showanswer cannot be None')
          if not self.my_osid_object_form._is_valid_string(
                  showanswer, self.get_showanswer_metadata()):
              raise InvalidArgument('showanswer')
          self.my_osid_object_form._my_map['showanswer'] = showanswer
docs: stub