def METHOD_NAME(target_dict, source_dict, key):
    if key not in target_dict:
        target_dict[key] = source_dict[key]
    elif not isinstance(target_dict[key], dict) or not isinstance(source_dict[key], dict):
        target_dict[key] = source_dict[key]
    else:
        for k in list(source_dict[key].keys()):
            METHOD_NAME(target_dict[key], source_dict[key], k)