1. from threading import lock
    2. from flask import Flask
    4. app = Flask(__name__)
    6. a = 1
    7. b = 1
    8. c = 3
    9. lock = Lock()
    11. @app.route("/")
    12. def hello():
    13.     with lock:
    14.         a += 1
    15.         b += a
    16.         c += b
    17.     return "Hello World!"
    19. if __name__ == "__main__":
    20.     app.run()