onClose(): How to distinguish between unestablished connections and opened connections?

[Tomforge]

I am writing a websocket server in Autobahn Python with the Twisted framework. Currently I am doing something like this:

class MyProtocol(WebSocketServerProtocol):
    def onOpen(self):
        # Do some initialization

    def onClose(self, wasClean, code, reason):
        # Do some cleanup

The problem is, denied/unable to be established websocket connections (which don't trigger `onOpen()`) triggers `onClose()`. Is there an Autobahn/Twisted way for me to perform cleanup only for previously opened connections, ignoring unestablished connections? Can i determine this from the error code alone, or should i just set a `self.wasOpen = True` flag in my protocol's `onOpen()`?