old_contents: #Abstract for all views
  class View(object):
      def __init__(self):
          self._renderer = None
  
      def render(self, glcontext):
          pass
  
new_contents: from Cura.View.ClassicGLRenderer import ClassicGLRenderer
  #from Cura.View.GL2Renderer import GL2Renderer
  
  ## Abstract base class for view objects.
  class View(object):
      def __init__(self):
          super(View, self).__init__()
          self._renderer = ClassicGLRenderer()
          self._controller = None
  
      def getController(self):
          return self._controller
  
      def getRenderer(self):
          return self._renderer
  
      def setController(self, controller):
          self._controller = controller
  
      def render(self, glcontext):
          pass
  
subject: Add getController, setController and getRenderer methods to View