python - PyUSB: Why are bus.dirname and dev.filename empty string? -


i new using pyusb. have usb devices connected machine , trying of properties. based on have learnt other examples using pyusb, have produced short program in linux. here snip of program:

busses = usb.busses()    bus in busses:        devices = bus.devices        dev in devices:           print dev.filename           print bus.dirname           print dev.idproduct

when checked output, both dev.filename , bus.dirname empty string devices. dev.idproduct correct.

can these questions please? (1) dev.filename? (2) bus.dirname? (3) can both of these properties empty?

thanks.


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