code: def pad(img, H, W):
      b, c, h, w = img.shape
      pad_h = (H - h) // 2
      pad_w = (W - w) // 2
      remainder_h = (H - h) % 2
      remainder_w = (W - w) % 2
      expand_img = nn.functional.pad(
          img, [pad_w, pad_w + remainder_w, pad_h, pad_h + remainder_h]
      )
      return expand_img
  
file_path: PaddleHub/modules/image/Image_gan/style_transfer/paint_transformer/render_utils.py
imports: import paddle
  import paddle.nn
  import paddle.nn.functional
  import cv2
  import numpy
  from PIL import Image
  import math
label_desc: Use image node_id 5 for calling a global function with example usage: pad(img, H, W) and returns: expand_img