class_docstr: Used in RetinaNet proposed in paper https://arxiv.org/pdf/1708.02002.pdf
      
class_docstr_tok: ["Used","in","RetinaNet","proposed","in","paper","https",":","\/\/arxiv.org\/pdf\/1708.02002.pdf"]
code: def post_process(self, head_outputs, im_shape, scale_factor):
      cls_logits_list, bboxes_reg_list = head_outputs
      anchors = self.anchor_generator(cls_logits_list)
      cls_logits = [_.transpose([0, 2, 3, 1]) for _ in cls_logits_list]
      bboxes_reg = [_.transpose([0, 2, 3, 1]) for _ in bboxes_reg_list]
      bboxes, scores = self.decode(
          anchors, cls_logits, bboxes_reg, im_shape, scale_factor
      )
  
      bbox_pred, bbox_num, nms_keep_idx = self.nms(bboxes, scores)
      return bbox_pred, bbox_num, nms_keep_idx
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import math
  import paddle
  import paddle.nn
  import paddle.nn.functional
  from paddle import ParamAttr
  from paddle.nn.initializer import Normal, Constant
  from ppdet.modeling.bbox_utils import bbox2delta, delta2bbox
  from ppdet.modeling.heads.fcos_head import FCOSFeat
  from ppdet.core.workspace import register
label_desc: Use image node_id 6 for calling the RetinaHead obj's underlying member method code with example usage: obj.post_process(head_outputs, im_shape, scale_factor) and returns: bbox_pred,  bbox_num,  nms_keep_idx