Any idea where this exception can come from?
Exception exceptions.ReferenceError: ‘weakly-referenced object no longer
exists’ in <bound method db_flexrf_2400_tx_mimo_b.del of
<gnuradio.db_flexrf_mimo.db_flexrf_2400_tx_mimo_b object at 0x8895c2c>>
The code does not explicitly delete the subdevice. I instantiate the
usrp object, then I retrieve a handle to the subdev to set gain etc.
Handles to usrp and subdev are stored in class members. The object
holding these handles is not destroyed before program end.