Deploy flask by wfastcgi to IIS, logging not work in blueprint

Question

I use python logging, it works well in simple code, when I deploy it on IIS using wfastcgi:

from flask import Flask
from LarkLog import LarkLog
app = Flask(__name__)

@app.route("/")
def hello():
    LarkLog.Debug('hello!')
    return "Hello Stealth!"

if __name__ == '__main__':
    # manager.run() 
    app.run(host='0.0.0.0', port=5003, debug=True)

But when I deploy my real project which using blueprint, it works well except logging module not work. It does not logging anything, but an empty log file created.

Any suggestion? Thanks!