
class MessagingHub(object):
    """
    A generic messaging hub.

    This class represents the base functionality of the protocol-level hubs.
    """

    def send_message(self, topic, message):
        raise NotImplementedError

    def subscribe(self, topic):
        raise NotImplementedError


class MessagingHub(object):
    """
    A generic messaging hub.

    This class represents the base functionality of the protocol-level hubs.
    """

    def send_message(self, topic, message):
        raise NotImplementedError

    def subscribe(self, topic, callback):
        raise NotImplementedError

Update our MessagingHub.subscribe method arguments
Update our MessagingHub.subscribe method arguments

  
  class MessagingHub(object):
      """
      A generic messaging hub.
  
      This class represents the base functionality of the protocol-level hubs.
      """
  
      def send_message(self, topic, message):
          raise NotImplementedError
  
-     def subscribe(self, topic):
+     def subscribe(self, topic, callback):
          raise NotImplementedError
  
Update our MessagingHub.subscribe method arguments
## Code Before:

class MessagingHub(object):
    """
    A generic messaging hub.

    This class represents the base functionality of the protocol-level hubs.
    """

    def send_message(self, topic, message):
        raise NotImplementedError

    def subscribe(self, topic):
        raise NotImplementedError

## Instruction:
Update our MessagingHub.subscribe method arguments
## Code After:

class MessagingHub(object):
    """
    A generic messaging hub.

    This class represents the base functionality of the protocol-level hubs.
    """

    def send_message(self, topic, message):
        raise NotImplementedError

    def subscribe(self, topic, callback):
        raise NotImplementedError
