请问如何配置多个按键

我想添加多个按键用以选择，可是部署失败。请问支持设置多个按键吗？怎样正确配置呢？
```yaml
key_binder:
select_first_character: "grave", "9"
select_last_character: "backslash", "0"
```

Start with the repository's key_binder configuration and the deployment path for the YAML snippet. Determine whether select_first_character and select_last_character can accept multiple values; done means a documented configuration that deploys successfully and lets each configured key perform selection.

Written by the indexing model from the issue text.