title: How to update webapp2_extras session in GAE based application
body: <p>I have two questions:</p>
  
  <ol>
  <li><p>First one is that Is it good practice to update a session (frequently) once it has been created? If no, then what are the possible issues which could occur?</p></li>
  <li><p>I am working on GAE based application and using webapp2_extras auth model provided by GAE for authentication. 
  I am trying to update the value of an attribute of session (after it has been created), but it does not seem to be working.</p></li>
  </ol>
  
  <p>The exact code piece is: </p>
  
  <pre><code>updates = {'fullname': 'sdsdsdsdsd'}
  self.auth.set_session_data(session, **updates)
  </code></pre>
  
  <p>but, it throws an error that:</p>
  
  <pre><code>TypeError: set_cookie() got an unexpected keyword argument 'fullname'
  </code></pre>
  
  <p>According to the documentation of the lib, it should work. As, it written that:</p>
  
  <pre><code>def set_session_data(self, data, **session_args):
      """Sets the session data as a list.
  
      :param data:
          Deserialized session data.
      :param session_args:
          Extra arguments for the session.
      """
      data = self.store.serialize_session(data)
      if data is not None:
          self.session['_user'] = data
          self.session.container.session_args.update(session_args)
  </code></pre>
  
  <p>Can anyone please help me here? Also, explains if I should be updating the session or not? I have a scenario where I will be doing that but it does not seem good to be. I think a session should not be updated manually once it has been created.</p>