title: Python class attribute seems to be resetting
body: <p>I have 2 files here, one is a player.py</p>
  
  <pre><code>class playerinfo:
      def __init__(self):
          self.playername=None
          self.authtoken=None
  </code></pre>
  
  <p>And in the main file I've got</p>
  
  <pre><code>from player import *
  p=playerinfo()
  class MenuScreen(Screen):
      def __init__(self, **kwargs):
          super(MenuScreen, self).__init__(**kwargs)
      def login(self, Username, Passwd):
          if logindata != "11":
              p.playername=Username
              p.authtoken=logindata[0]
  
  
  class PlayerScreen(Screen):
      def __init__(self, **kwargs):
          super(PlayerScreen, self).__init__(**kwargs)
      print(p.playername)
  </code></pre>
  
  <p>My problem is in the PlayerScreen class p.playername returns as None as set in playerinfo()
  If I print p.playername in the MenuScreen class it prints out the playername correctly.</p>