Runtime error in markup with attrs in checklists

Markdown markup:
```md
[ ] checklist {#class}
```

When call `transform()` and pass this markup and `checkbox`-plugin, a runtime error occurs:
```
Uncaught TypeError: Cannot read properties of undefined (reading 'type')
at push../node_modules/markdown-it-attrs/utils.js.exports.getMatchingOpeningToken (utils.js:236:1)
at Object.transform (patterns.js:328:1)
at Array.curlyAttrs (index.js:30:1)
at push../node_modules/markdown-it/lib/parser_core.js.Core.process (parser_core.js:54:1)
at push../node_modules/markdown-it/lib/index.js.MarkdownIt.parseInline (index.js:561:1)
at createTokens (checkbox.js:67:1)
at splitTextToken (checkbox.js:89:1)
at Array. (checkbox.js:98:1)
at push../node_modules/markdown-it/lib/parser_core.js.Core.process (parser_core.js:54:1)
at push../node_modules/markdown-it/lib/index.js.MarkdownIt.parse (index.js:524:1)
```