'Returns a flat tuple of all known trackers
@return A tuple containing trackers'

def get_trackers_as_single_tuple(self):

    if self.get_tracker_hierarchy():
        trackers = []
        for level in self.get_tracker_hierarchy():
            for tracker in level:
                if (tracker and (tracker not in trackers)):
                    trackers.append(tracker)
        return tuple(trackers)
    tracker = self.get_tracker()
    if tracker:
        return (tracker,)
    return ()
