old_contents: """
  Classes meant to represent the PubSubHubbub Hub.
  
  The hub itself does not have state, but does hold references to
  subscribers and topics.
  """
  
  from zope.component import provideUtility
  from zope.interface import Interface, implements
  
  
  from repoze.folder import Folder
  
  
  class IHub(Interface):
      """Marker interface for hub implementations"""
      pass
  
  
  class Hub(Folder):
      implements(IHub)
      __name__ = __parent__ = None
  
      def __init__(self):
          self.topics = None
          self.subscribers = None
  
      def publish(self):
          """
          Publish a topic to a particular feed
          """
          pass
  
      def notify_subscribers(self):
          """
          Sends updates to each of the subscribers to let them know
          of new topic content.
          """
          pass
  
new_contents: """
  Classes meant to represent the PubSubHubbub Hub.
  
  The hub itself does not have state, but does hold references to
  subscribers and topics.
  """
  
  from zope.interface import Interface, implements
  
  
  from repoze.folder import Folder
  
  
  class IHub(Interface):
      """Marker interface for hub implementations"""
      pass
  
  
  class Hub(Folder):
      implements(IHub)
      __name__ = __parent__ = None
      title = "Hub"
  
      def __init__(self):
          self.topics = None
          self.subscribers = None
  
      def publish(self):
          """
          Publish a topic to a particular feed
          """
          pass
  
      def notify_subscribers(self):
          """
          Sends updates to each of the subscribers to let them know
          of new topic content.
          """
          pass
  
subject: Remove unused import, add a title for the hub object.