code: def get_loss(self):
      return self._forward()
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import paddle
  import numpy
  import math
  import cv2
  from ppdet.core.workspace import register, create
  from .meta_arch import BaseArch
  from ..keypoint_utils import transform_preds
  from ..None import layers
  from paddle.nn import functional
label_desc: Use image node_id 4 for calling the TopDownHRNet obj's underlying member method code with example usage: obj.get_loss() and returns: self