setup-python/.github/python.json

{
    "problemMatcher": [
        {
            "owner": "python",
            "pattern": [
                {
                    "regexp": "^\\s*File\\s\\\"(.*)\\\",\\sline\\s(\\d+),\\sin\\s(.*)$",
                    "file": 1,
                    "line": 2,
                    "message": 3
                }
            ]
        }
    ]
}