code: def apply_bbox(self, bbox0, h, w, ratio, padw, padh):
      bboxes = bbox0.copy()
      bboxes[:, 0] = ratio * w * (bbox0[:, 0] - bbox0[:, 2] / 2) + padw
      bboxes[:, 1] = ratio * h * (bbox0[:, 1] - bbox0[:, 3] / 2) + padh
      bboxes[:, 2] = ratio * w * (bbox0[:, 0] + bbox0[:, 2] / 2) + padw
      bboxes[:, 3] = ratio * h * (bbox0[:, 1] + bbox0[:, 3] / 2) + padh
      return bboxes
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from numbers import Integral
  import cv2
  import copy
  import numpy
  import random
  import math
  from .operators import BaseOperator, register_op
  from .batch_operators import Gt2TTFTarget
  from ppdet.modeling.bbox_utils import bbox_iou_np_expand
  from ppdet.utils.logger import setup_logger
  from .op_helper import gaussian_radius
label_desc: Use image node_id 3 for calling the LetterBoxResize obj's underlying member method code with example usage: obj.apply_bbox(bbox0, h, w, ratio, padw, padh) and returns: bboxes