Can Vader work with Vim9 script?

Such a code passes (and it expectedly fails if I change the second argument to `AssertEqual`), suggesting that Vader is indeed executing Vim9 script code:
```vader
Execute (vim9 var):
vim9cmd var path = '/some/path/to/file.txt'
AssertEqual path, '/some/path/to/file.txt'
```

But if I write this
```
Execute (vim9 lambda):
vim9cmd var Identity = (x) => x
AssertEqual Identity(3), 3
```
it fails like this
```
Starting Vader: 1 suite(s), 1 case(s)
Starting Vader: /home/enrico/.vim/plugged/WinZoZ/test/winzoz.vader
(1/1) [EXECUTE] vim9 lambda
(1/1) [EXECUTE] (X) Vim(call):E117: Unknown function: Identity
> command line..function 24_vader[5]..vader#run[63]..96_run[42]..96_execute[2]..vader#window#execute[11]..script /tmp/vvIdE4r/3, line 2
Success/Total: 0/1
Success/Total: 0/1 (assertions: 0/0)
Elapsed time: 0.01 sec.
Failure
```
suggesting that something is not quite right...

Anybody knows?