Couldn't we achieve the same functionality with a little less ambiguity using the following syntax?:

    not_found = 404
    match status:
        case not_found:
            return "Not found"
            
        case _ as foo:
            do_something(foo)
            return "Match anything"

    match json_pet:
        case {"type": "cat", "name": _ as name, "pattern": _ as pattern}:
            return Cat(name, pattern)
        case {"type": "dog", "name": _ as name, "breed": _ as breed}:
            return Dog(name, breed)
        case _:
            raise ValueError("Not a suitable pet")