title: importerror: no module named flask.ext.script
body: <p>In fact I cannot use any pakage now!</p>
  
  <p><a href="http://i.stack.imgur.com/dARhF.png" rel="noreferrer">importerror: no module named flask.ext.script</a></p>
  
  <p><a href="http://i.stack.imgur.com/DDFfY.png" rel="noreferrer">importerror: no module named Pymongo</a></p>