From a child repo I want to be able to call base print_version binary with the toolchain defined inside base.

Something like this:
```
bazel run @base//:print_version
```
or this:
```
bazel run @base//:print_version --extra_toolchains=@base_python_toolchains//:x86_64-unknown-linux-gnu_toolchain
```

The problem is that I don't control which child's rules_python version nor how its configuration.

Is it possible to achieve this behaviour using rules_python toolchains or should I create my own?