如何查询嵌套很深的json文档？

import json

def find_nested_node(json_data, target_key):
    if isinstance(json_data, dict):
        for key, value in json_data.items():
            if key == target_key:
                return value
            elif isinstance(value, (dict, list)):
                result = find_nested_node(value, target_key)
                if result is not None:
                    return result
    elif isinstance(json_data, list):
        for item in json_data:
            result = find_nested_node(item, target_key)
            if result is not None:
                return result

# 示例JSON文档
json_doc = '''
{
    "name": "John",
    "age": 30,
    "address": {
        "street": "123 Main St",
        "city": "New York",
        "country": "USA"
    },
    "contacts": [
        {
            "type": "email",
            "value": "john@example.com"
        },
        {
            "type": "phone",
            "value": "123-456-7890"
        }
    ]
}
'''

# 解析JSON文档
data = json.loads(json_doc)

# 查询嵌套节点
result = find_nested_node(data, "city")
print(result)  # 输出：New York