def f(a, b):
    if isinstance(a, dict):
        return {k: f(a[k], b[k]) if k in a and k in b else a.get(k, b.get(k)) for k in a.keys() | b.keys()}
    elif isinstance(a, list):
        main = {}
        for i in [*a, *b]:
            main = f(main, i)
        return [main]

    return a