def METHOD_NAME(bboxes, im_w, im_h, letterbox_w, letterbox_h):
    '''
    The predicted bounding box coordinates from the model are not according to original image but the pre-processed image. This function transforms the coorinates
    according to original image by applying inverse letterbox co-rdinate trasforms mathematically.
    Args:
        bboxes: 
             The bounding box coordinates predicted from the model.
        im_w : 
             Width of original input image.
        im_h :
             Height of original input image.
    '''
    bboxes = bboxes.copy()
    for bb in bboxes:
        x, y, w, h = bb[:4]
        x1 = (x - (1 - letterbox_w) / 2.) / letterbox_w * im_w
        y1 = (y - (1 - letterbox_h) / 2.) / letterbox_h * im_h
        w1 = w * im_w / letterbox_w
        h1 = h * im_h / letterbox_h
        bb[:4] = x1, y1, w1, h1
    return bboxes