def box_iou(boxes1: np.array, boxes2: np.array) -> np.array:
    """
    Return intersection-over-union (Jaccard index) of boxes.

    Both sets of boxes are expected to be in ``(x1, y1, x2, y2)`` format with
    ``0 <= x1 < x2`` and ``0 <= y1 < y2``.

    Args:
        boxes1 (Tensor[N, 4])
        boxes2 (Tensor[M, 4])

    Returns:
        iou (Tensor[N, M]): the NxM matrix containing the pairwise IoU values for every element in boxes1 and boxes2
    """
    inter, union = _box_inter_union(boxes1, boxes2)
    iou = inter / union
    return iou

    Return intersection-over-union (Jaccard index) of boxes.

    Both sets of boxes are expected to be in ``(x1, y1, x2, y2)`` format with
    ``0 <= x1 < x2`` and ``0 <= y1 < y2``.

    Args:
        boxes1 (Tensor[N, 4])
        boxes2 (Tensor[M, 4])

    Returns:
        iou (Tensor[N, M]): the NxM matrix containing the pairwise IoU values for every element in boxes1 and boxes2
    
kosmos-2/evaluation/flickr_entities/flickr_entities_evaluate.py