code: def update(self, index, value):
      self.sum_tree[index] = value
      self._propagate(index, value)
      self.max = max(value, self.max)
  
file_path: SerpentAI/serpent/machine_learning/reinforcement_learning/rainbow_dqn/segment_tree.py
label_desc: Use image node_id 2 for calling the SegmentTree obj's underlying member method code with example usage: obj.update(index, value) without return types