def signal_handler(signal, frame):
  logging.warning("Caught signal: {0}".format(signal))
  IOLoop.instance().add_callback(shutdown)
It is possible to inject new schemes at runtime
dataset/ETHPy150Open AppScale/appscale/Hermes/hermes.py/signal_handler--crossover with--dataset/ETHPy150Open getsentry/raven-python/raven/transport/registry.py/TransportRegistry.register_scheme