Flask教程效果做不出来,谁来帮帮我NameError，flasknameerror,教程地址:http://

教程地址:http://docs.jinkan.org/docs/flask/tutorial/dbinit.html#tutorial-dbinit

# all the imports                                          import sqlite3from flask import Flask, request, session, g, redirect, url    _for, abort, render_template, flash# configurationDATABASE = '/tmp/flaskr.db'DEBUG = TrueSECRET_KEY = 'development key'USERNAME = 'admin'PASSWORD = 'default'#create our little application app = Flask(__name__)app.config.from_envvar('FLASKR_SETTINGS', silent=True)def connect_db():    return sqlite3.connect(app.config['DATABASE'])def init_db():    with closing(connect_db()) as db:        with app.open_resource('schema.sql') as f:            db.cursor().executescript(f.read())        db.commit()if __name__ == '__main__':    app.run()

在Python shell 里创建数据库这一步报如下错误:

>>> init_db()Traceback (most recent call last):  File "<stdin>", line 1, in <module>  File "flaskr.py", line 18, in init_db    with closing(connect_db()) as db:NameError: global name 'closing' is not defined

编橙之家文章，