# demo2.py
import json

def main():
    result = {
        "message": "Hello, World!",
        "value": 42,
        "list": [1, 2, 3],
        "dict": {"key1": "value1", "key2": "value2"}
    }
    json_result = json.dumps(result)
    print(json_result)

if __name__ == "__main__":
    main()