'return a string with USB related information about device'

def usb_info(self):

    return 'USB    VID:PID={:04X}:{:04X}{}{}'.format((self.vid or 0), (self.pid or 0), ('    SER={}'.format(self.serial_number) if (self.serial_number is not None) else ''), ('    LOCATION={}'.format(self.location) if (self.location is not None) else ''))
