如何用Python优雅地打印多层嵌套JSON数据的树状结构？

import json

def print_json_tree(json_obj, indent=0):
    """递归函数，以树状结构打印JSON数据"""
    if isinstance(json_obj, dict):
        for key, value in json_obj.items():
            print('  ' * indent + f'{key}:') # 使用f-string更简洁
            print_json_tree(value, indent + 1)
    elif isinstance(json_obj, list):
        for i, item in enumerate(json_obj):
            print('  ' * indent + f'[{i}]:')
            print_json_tree(item, indent + 1)
    else:
        print('  ' * indent + str(json_obj))

# 示例JSON数据
json_str = '''
{
  "id":"series","css":"wrapper","html":[
    {"id":"series","css":"header","html":[
        {"css":"topbar","html":[
            {"css":"left","html":[]},
            {"css":"middle","html":[]},
            {"css":"right","html":[]}
        ]},
        {"css":"mask","html":[]},
        {"css":"layer","html":[]}
    ]},
    {"id":"series","css":"container","html":[
        {"id":"series","css":"container ad1200 mt10","html":[]},
        {"id":"series","css":"container crumb","html":[]},
        {"id":"series","css":"container nav","html":[]},
        {"id":"series","css":"series_wrapper","html":[
            {"id":"series","css":"main","html":[
                {"pic":"","total":""},
                {"news1":"","new2":""},
                {"ad1":""},
                {"list":""},
                {"pic":""},
                {"video":""},
                {"ad2":""}
            ]},
            {"id":"series","css":"side","html":[
                {"ad3":"google"},
                {"love":""},
                {"brand":""},
                {"type":""}
            ]}
        ]}
    ]},
    {"position":[
        {"return_top":""},
        {"side_nav":""}
    ]},
    {"footer":[
        {"nav":""}
    ]}
]
}
'''

json_obj = json.loads(json_str)
print_json_tree(json_obj)