`cmd - f7` hotkey supported?

I want `lcmd` + `f7` to execute a yabai command. I exhaustively try in my `.skhdrc`
```sh
lcmd - f7 : yabai -m space --focus 2
```
and
```sh
lcmd - kVK_F7 : yabai -m space --focus 2
```
and
```sh
lcmd - 62 : yabai -m space --focus 2
```
all without success.

I try to confirm what keycode `skhd` recognizes `f7` as with `skhd -o`, but nothing outputs when pressing `f7`.

Is using the fn keys within a hotkey shortcut supported?

Reproduce the examples from .skhdrc and observe skhd -o while pressing F7. Trace how function-key events and the shown keycode forms are recognized, then determine whether F7 can be bound. Done means confirming supported syntax or defining the implementation and documentation changes needed to support it.

Written by the indexing model from the issue text.