def reorder(items, before):
    """ Move one or more items from a folder into new positions inside that
        folder. ``items`` is a list of ids of existing folder items, which will
        be inserted in order before the item named ``before``. All other items
        are left in the original order.  If this method is called on a folder
        which does not have an order set, or which is not reorderable, a
        :exc:`ValueError` will be raised."""
