Почему пакет компилятора прекращен в Python 3?

private void btnUp_Click(object sender, System.EventArgs e)
{
    if (this.lbItems.SelectedIndex == -1 || this.lbItems.SelectedIndex == 0)
        return;

        Object select, previous, temp;
        select = lbItems.Items[lbItems.SelectedIndex];
        previous = lbItems.Items[lbItems.SelectedIndex-1];
        temp = select;
        select = previous;
        previous = temp;

        lbItems.Items[lbItems.SelectedIndex] = select;
        lbItems.Items[lbItems.SelectedIndex-1] = previous;

        lbItems.SelectedIndex--;            
}

private void btnDown_Click(object sender, System.EventArgs e)
{
    if (this.lbItems.SelectedIndex == -1 || this.lbItems.SelectedIndex == lbItems.Items.Count-1)
        return;     

    Object select, next, temp;
    select = lbItems.Items[lbItems.SelectedIndex];
    next = lbItems.Items[lbItems.SelectedIndex+1];
    temp = select;
    select = next;
    next = temp;

    lbItems.Items[lbItems.SelectedIndex] = select;
    lbItems.Items[lbItems.SelectedIndex+1] = next;
    lbItems.SelectedIndex++;
}