features/test-scenarios/scenarios.json

{
    "install_python_twice": {
        "image": "mcr.microsoft.com/vscode/devcontainers/base:focal",
        "features": [
            {
                "id": "python",
                "options": {
                    "version": "3.8"
                }
            },
            {
                "id": "python",
                "options": {
                    "version": "3.9",
                    "overrideDefaultVersion": true
                }
            }
        ]
    }
}