parameters: (self, message_listener)
docstring: Internal method used by the protocol message implementation.
      Clients should not call this directly.
  
      Sets a listener that this message will call on certain state transitions.
  
      The purpose of this method is to register back-edges from children to
      parents at runtime, for the purpose of setting "has" bits and
      byte-size-dirty bits in the parent and ancestor objects whenever a child or
      descendant object is modified.
  
      If the client wants to disconnect this Message from the object tree, she
      explicitly sets callback to None.
  
      If message_listener is None, unregisters any existing listener.  Otherwise,
      message_listener must implement the MessageListener interface in
      internal/message_listener.py, and we discard any listener registered
      via a previous _SetListener() call.
docstring_summary: Internal method used by the protocol message implementation.
      Clients should not call this directly.
docstring_tokens: Internal method used by the protocol message implementation . Clients should not call this directly .
function: def _SetListener(self, message_listener):
      """Internal method used by the protocol message implementation.
      Clients should not call this directly.
  
      Sets a listener that this message will call on certain state transitions.
  
      The purpose of this method is to register back-edges from children to
      parents at runtime, for the purpose of setting "has" bits and
      byte-size-dirty bits in the parent and ancestor objects whenever a child or
      descendant object is modified.
  
      If the client wants to disconnect this Message from the object tree, she
      explicitly sets callback to None.
  
      If message_listener is None, unregisters any existing listener.  Otherwise,
      message_listener must implement the MessageListener interface in
      internal/message_listener.py, and we discard any listener registered
      via a previous _SetListener() call.
      """
      raise NotImplementedError
function_tokens: def _SetListener ( self , message_listener ) : raise NotImplementedError