def chunkBox(self, level):
        """Returns this box extended to the chunk boundaries of the given level"""
        box = self
        return BoundingBox((box.mincx << 4, 0, box.mincz << 4),
                           (box.maxcx - box.mincx << 4, level.Height, box.maxcz - box.mincz << 4))
Returns this box extended to the chunk boundaries of the given level
pymclevel/box.py