code: def discover(cls, device, timeout_sec=TIMEOUT_SEC):
          
          device.discover(cls.SERVICES, cls.CHARACTERISTICS, timeout_sec)
docs: Wait until the specified device has discovered the expected services
          and characteristics for this service.  Should be called once before other
          calls are made on the service.  Returns true if the service has been
          discovered in the specified timeout, or false if not discovered.