Extracting the coordinates of multiple Bounding box coordinates via video object detection

I am not able to extract the multiple coordinates of the bounding boxes by using the below code
can someone help me how to extract multiple coordinates?

box = np.squeeze(boxes)
for i in range(len(boxes)):
ymin = (int(box[i, 0] * height))
xmin = (int(box[i, 1] * width))
ymax = (int(box[i, 2] * height))
xmax = (int(box[i, 3] * width))

            print(ymin,xmin,ymax,xmax)
            roi = image_np[ymin:ymax, xmin:xmax].copy()