human
Give me a the Python program you requested given the following:
Complete the below
def formatted_loopback_device_for_test(test_case, label=None):

    ''''Create a loopback device, with a backing file located in the temporary
    directory for this test case.
    Format it with ext4 and optionally add a filesystem label.
    Registers test cleanup callbacks to unmount and detach the loopback device
    when the test is complete.
    :returns: A ``LoopDevice``.'
    '''
assistant
#Here is the Python program you requested.
    losetup = Losetup()
    backing_file = test_case.make_temporary_file()
    with backing_file.open('wb') as f:
        f.truncate(LOOPBACK_MINIMUM_ALLOCATABLE_SIZE)
    device = losetup.add(backing_file=backing_file)
    bdm = BlockDeviceManager()
    bdm.make_filesystem(blockdevice=device.device, filesystem=u'ext4')
    if label:
        run_process(['tune2fs', '-L', label, device.device.path])
    def cleanup():
        '\n                                Try    to    unmount    the    device    10    times    or    until    it    detaches.\n                                '
        device.remove()
        for _ in xrange(10):
            if (device in losetup.list()):
                _unmount(path=device.device, idempotent=True)
            else:
                break
    test_case.addCleanup(cleanup)
    return device