嵌套Json问题ı如何获取这些数据？

import json

def get_nested_data(json_data, keys):
    if len(keys) == 1:
        return json_data.get(keys[0])
    else:
        key = keys[0]
        if key in json_data:
            return get_nested_data(json_data[key], keys[1:])
        else:
            return None

# 示例嵌套Json数据
json_str = '''
{
  "name": "John",
  "age": 30,
  "address": {
    "street": "123 Street",
    "city": "New York",
    "country": "USA"
  }
}
'''

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

# 获取嵌套Json数据中的字段
keys = ["address", "city"]
city = get_nested_data(data, keys)
print(city)  # 输出：New York