python语句执行

python文件中的语句，按顺序执行，执行import时，原文件会入栈，等import文件执行完成后，才会出栈执行。
load/const.py
---
import os
DB_ADDRESS = os.getenv("DB_ADDRESS", "10.63.132.xxx:27017")

load/main.py
---
import os
from load.const import DB_ADDRESS

if __name__ == "__main__":
    os.environ["DB_ADDRESS"] = "xx"
    print(DB_ADDRESS)

> python load/main.py
输出:
10.63.132.xxx:27017