构建一个模块化的 Python 学习项目，涵盖从基础语法到面向对象编程的核心知识点。每个模块都包含功能代码与测试代码 ...

os.path.join (folder, filename) ensures the path is correct for the system. On Windows, it uses backslashes (reports\summary.txt); on Linux and macOS it uses forward slashes (reports/summary.txt).

This project fetches small datasets from the web, processes them with Python, and writes outputs (CSV, Excel, JSON, Text). Logging is handled by utils_logger.py.