Yield on Worker._start rather than Worker.start
@@ -223,7 +223,7 @@ def main(scheduler, host, worker_port, listen_address, contact_address,
@gen.coroutine
def run():
- yield [n.start(addr) for n in nannies]
+ yield [n._start(addr) for n in nannies]
while all(n.status != 'closed' for n in nannies):
yield gen.sleep(0.2)
