code: def register_service(service):
      
      frame = inspect.currentframe()
      m_name = frame.f_back.f_globals['__name__']
      m = sys.modules[m_name]
      m._SERVICE_NAME = service
docs: Register the ryu application specified by 'service' as
      a provider of events defined in the calling module.
  
      If an application being loaded consumes events (in the sense of
      set_ev_cls) provided by the 'service' application, the latter
      application will be automatically loaded.
  
      This mechanism is used to e.g. automatically start ofp_handler if
      there are applications consuming OFP events.