_removeReceiver, NoneType object has no attribute print_exc
Sometimes...
Maybe when the device was killed
Exception during saferef BoundMethodWeakref(<SpecClient_gevent.SpecChannel.SpecChannel instance at 0x7f09d5eafe10>.connected) cleanup function <function _removeReceiver at 0x7f09c5742ed0>: 'NoneType' object has no attribute 'print_exc'