title: Integrate facebook login in google app engine with python
body: <p>I created google app engine app.</p>
  
  <p>In that i used google direct login as well as login with openid.</p>
  
  <p>openid i integrate using do_openid_login.py as google document suggested.
  Now i want integrate facebook login too.</p>
  
  <p>So how could i integrate facebook login?</p>