Setting multiple Python versions via `asdf shell` doesn't seem to work

Thanks for this plugin! When I set multiple Python versions using `asdf global` or `asdf local`, everything works just as advertised and `asdf current python` says something like:

```
python 3.9.10 3.10.2 /Users/cecpe2/myproject/.tool-versions
```

However, when I use `asdf shell python 3.10.2 3.9.10`, `asdf current python` says:

```
python 3.10.2 ASDF_PYTHON_VERSION environment variable
```

Only the first version I listed is activate. Is this intended?