如何从JSON中提取循环密钥？

import json

def extract_recursive_keys(json_data):
    keys = []
    if isinstance(json_data, dict):
        for key, value in json_data.items():
            keys.append(key)
            if isinstance(value, dict):
                keys.extend(extract_recursive_keys(value))
    return keys

# 示例JSON数据
json_str = '''
{
    "key1": "value1",
    "key2": {
        "subkey1": "subvalue1",
        "subkey2": {
            "subsubkey1": "subsubvalue1"
        }
    },
    "key3": "value3"
}
'''

# 解析JSON数据
data = json.loads(json_str)

# 提取循环密钥
recursive_keys = extract_recursive_keys(data)

# 打印循环密钥
print("循环密钥：")
for key in recursive_keys:
    print(key)

循环密钥：
subkey2