def dict_depth(obj: dict):
    """get the depth of dict
    https://www.geeksforgeeks.org/python-find-depth-of-a-dictionary/
    e.g., {'a': {'b': 1}} has depth of 2
    """
    if isinstance(obj, dict):
        return 1 + (max(map(dict_depth, obj.values()))
                    if obj else 0)
    return 0