code: def get_loss(output, target_category):
      loss = 0
      for i in range(len(target_category)):
          loss = loss + output[i, target_category[i]]
      return loss
  
imports: import cv2
  import numpy
label_desc: Use image node_id 3 for calling the GradCAM obj's underlying member method code with example usage: obj.get_loss(output, target_category) and returns: loss