Code:

uchar   usbFunctionSetup(uchar data[8])
{
    usbRequest_t *rq = (void *)data;
    if((rq->bmRequestType & USBRQ_TYPE_MASK) == USBRQ_TYPE_STANDARD){    
        if(rq->bRequest == USBRQ_GET_INTERFACE){  
            return USB_NO_MSG;  /* use usbFunctionWrite() to receive data from host */
        }else if(rq->bRequest == USBRQ_SET_INTERFACE){
            return USB_NO_MSG;  /* use usbFunctionWrite() to receive data from host */
        }
    }
    return 0;
}

Code:

import usb1, libusb1

bmRequestType=libusb1.LIBUSB_TYPE_CLASS | libusb1.LIBUSB_ENDPOINT_IN
bRequest=libusb1.LIBUSB_REQUEST_SET_CONFIGURATION
buf=chr(0)+chr(0)+chr(0)

context = usb1.USBContext()
deviceList=context.getDeviceList(skip_on_error=True)
for device in deviceList:
    if '16c0:05df' in str(device):
        deviceName=device.getProduct()
        if deviceName=='ISM_RTX':
            usbHandle=device.open()
            print usbHandle.controlWrite(bmRequestType, bRequest, 0, 0, buf,0)