def METHOD_NAME(app,
                          concurrency=1,
                          pool='solo',
                          loglevel=WORKER_LOGLEVEL,
                          logfile=None,
                          **kwargs):
    # type (Celery, int, str, Union[int, str], str, **Any) -> Iterable
    """Start worker in separate process.
    Yields:
        celery.app.worker.Worker: worker instance.
    """
    from celery.apps.multi import Cluster, Node
    app.set_current()
    cluster = Cluster([Node('testworker1@%h')])
    cluster.start()
    try:
        yield
    finally:
        cluster.stopwait()