old_contents: from flask import request, url_for, redirect,session
  from app import app
  import os
  from oauth2client import client
  import StringIO
  import json
  
  
  @app.route('/logout/', methods=['GET', 'POST'])
  def logout(provider_name):
      """
      Logout, must accept both GET and POST to be able to use OpenID.
      """
      del session['credentials']
      return redirect(url_for("index"))
  
new_contents: from flask import request, url_for, redirect,session
  from app import app
  import os
  from oauth2client import client
  import StringIO
  import json
  
  
  @app.route('/logout/')
  def logout():
      """
      Logout, must accept both GET and POST to be able to use OpenID.
      """
      session.pop('credentials', None)
      flash("You were logged out")
      return redirect(url_for("index"))
  
subject: fix logout method