流石に`AbstractGroup.keyword`が全ての中でユニークというのは考えられない． <!-- Edit the body of your new issue then click the ✓ "Create Issue" button in the top right of the editor. The first line will be the issue title. Assignees and Labels follow after a blank line. Leave an empty line before beginning the body of the issue. -->
流石に
AbstractGroup.keywordが全ての中でユニークというのは考えられない．