title: Flask Beaker session "AttributeError: 'Session' object has no attribute 'permanent'"
body: <p>I'm using Beaker with Memcached for session management in a Flask based application, but I'm getting "AttributeError: 'Session' object has no attribute 'permanent'" while logging out a user also sometimes when the user session is active.
  See Error Below</p>
  
  <pre><code>  File "/home/hirealchemy/hirealchemy_v2/local/lib/python2.7/site-packages/flask/templating.py", line 126, in render_template
      ctx.app.update_template_context(context)
    File "/home/hirealchemy/hirealchemy_v2/local/lib/python2.7/site-packages/flask/app.py", line 716, in update_template_context
      context.update(func())
    File "/home/hirealchemy/hirealchemy_v2/local/lib/python2.7/site-packages/flask_login.py", line 826, in _user_context_processor
      return dict(current_user=_get_user())
    File "/home/hirealchemy/hirealchemy_v2/local/lib/python2.7/site-packages/flask_login.py", line 795, in _get_user
      current_app.login_manager._load_user()
    File "/home/hirealchemy/hirealchemy_v2/local/lib/python2.7/site-packages/flask_login.py", line 340, in _load_user
      deleted = self._session_protection()
    File "/home/hirealchemy/hirealchemy_v2/local/lib/python2.7/site-packages/flask_login.py", line 383, in _session_protection
      if mode == 'basic' or sess.permanent:
    File "/home/hirealchemy/hirealchemy_v2/local/lib/python2.7/site-packages/beaker/session.py", line 663, in __getattr__
      return getattr(self._session(), attr)
  AttributeError: 'Session' object has no attribute 'permanent'
  </code></pre>