如何从嵌套字典中提取键值对并将其输出到json中

import json

def extract_dict(data, result):
    for key, value in data.items():
        if isinstance(value, dict):
            extract_dict(value, result)
        else:
            result[key] = value

def extract_to_json(data):
    result = {}
    extract_dict(data, result)
    return json.dumps(result)

# 示例嵌套字典
nested_dict = {
    "key1": "value1",
    "key2": {
        "nested_key1": "nested_value1",
        "nested_key2": "nested_value2"
    },
    "key3": "value3"
}

# 提取键值对并输出到JSON
json_output = extract_to_json(nested_dict)
print(json_output)

{"key1": "value1", "nested_key1": "nested_value1", "nested_key2": "nested_value2", "key3": "value3"}