def get_bbox_from_gt(gt_root):
    """ Get the all the supervised bounding boxes (ground truth) having `gt_root` as root folder.

    :param gt_root: root folder for the ground truth bounding boxes
    :return all_objs: all supervised bounding boxes
    """
    all_objs = dict()

    all_objs_elem = gt_root.findall("./object")
    for obj_elem in all_objs_elem:
        id = obj_elem.find("./name").text

        if id not in all_objs.keys():
            all_objs[id] = []

        bbox_elem = obj_elem.find("./bndbox")

        xmin = int(bbox_elem.find("./xmin").text) - 1
        ymin = int(bbox_elem.find("./ymin").text) - 1
        xmax = int(bbox_elem.find("./xmax").text)
        ymax = int(bbox_elem.find("./ymax").text)

        all_objs[id].append((xmin, xmax, ymin, ymax))
    return all_objs