code: def forward(self, inputs):
      img = inputs[0]
      relations, texts, gt_bboxes, tag, img_size = (
          inputs[1],
          inputs[2],
          inputs[3],
          inputs[5],
          inputs[-1],
      )
      img, relations, texts, gt_bboxes = self.pre_process(
          img, relations, texts, gt_bboxes, tag, img_size
      )
      x = self.img_feat(img)
      boxes, rois_num = self.bbox2roi(gt_bboxes)
      feats = paddle.vision.ops.roi_align(
          x, boxes, spatial_scale=1.0, output_size=7, boxes_num=rois_num
      )
      feats = self.maxpool(feats).squeeze(-1).squeeze(-1)
      return [relations, texts, feats]
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import paddle
  from paddle import nn
  import numpy
  import cv2
label_desc: Use image node_id 4 for calling the Kie_backbone obj's underlying member method code with example usage: obj.forward(inputs) and returns: list