PyUSB 1.0.0a1 issue (vs. 1.0.0a0)

#!/usr/bin/env python

import usb.core
import usb.util

def get_device(vendor, product):
    device = (vendor<<16)+product
    dev = usb.core.find(idVendor=vendor, idProduct=product)
    if not dev:
        raise ValueError('Device not found')
    for configuration in dev:
        # we need to detach any kernel driver from the device
        # be greedy: reclaim all device interfaces from the kernel
        for interface in configuration:
            ifnum = interface.bInterfaceNumber
            if not dev.is_kernel_driver_active(ifnum):
                continue
            try:
                dev.detach_kernel_driver(ifnum)
            except usb.core.USBError, e:
                pass
    dev.set_configuration()
    return dev

def open_device(vendor=0x403, product=0x6011, interface=1):
    DEV_OUT_REQTYPE = (usb.util.CTRL_TYPE_VENDOR << 5) | \
                       usb.util.CTRL_RECIPIENT_DEVICE | \
                       usb.util.CTRL_OUT
    SIO_RESET = 0 # Reset the port
    SIO_RESET_SIO = 0
    TIMEOUT = 5000
    usb_dev = get_device(vendor, product)
    usb_dev.ctrl_transfer(DEV_OUT_REQTYPE,
                          SIO_RESET,
                          SIO_RESET_SIO,
                          interface, '', TIMEOUT)
    return usb_dev

def main():
    print open_device()

if __name__ == '__main__':
    # PYTHONPATH=. pyusb100a0/bin/python snippet.py
    # PYTHONPATH=. pyusb100a1/bin/python snippet.py
    main()