<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def startReceivingBoxes(self, sender):
 """ Initialize route tracking objects. """

        self._sender = sender
        for routeName, route in self._unstarted.iteritems():
            # Any route which has been bound but which does not yet have a
            # remote route name should not yet be started.  These will be
            # started in Route.connectTo.
            if route.remoteRouteName is not _unspecified:
                route.start()
        self._routes = self._unstarted
        self._unstarted = None