code: def insert_values(self):
          
          if self._insert_values is None:
              self._insert_values = self._prepare_insert(
                  tmpl=self._insert_values_tmpl,
                  placeholder_for_id=True,
                  record_class=self.record_class,
                  field_names=self.field_names,
              )
          return self._insert_values
docs: SQL statement that inserts records without ID.