Check the context for the notifier and construct it if not present

def _get_queue(config):
    '''
    Check the context for the notifier and construct it if not present
    '''

    if 'watchdog.observer' not in __context__:
        queue = collections.deque()
        observer = Observer()
        for path in config.get('directories', {}):
            path_params = config.get('directories').get(path)
            masks = path_params.get('mask', DEFAULT_MASK)
            event_handler = Handler(queue, masks)
            observer.schedule(event_handler, path)

        observer.start()

        __context__['watchdog.observer'] = observer
        __context__['watchdog.queue'] = queue

    return __context__['watchdog.queue']