code: def _reduce_helper(self, start, end, node, node_start, node_end):
      if start == node_start and end == node_end:
          return self._value[node]
      mid = (node_start + node_end) // 2
      if end <= mid:
          return self._reduce_helper(
              start, end, 2 * node, node_start, mid
          )
      else:
          if mid + 1 <= start:
              return self._reduce_helper(
                  start, end, 2 * node + 1, mid + 1, node_end
              )
          else:
              return self._operation(
                  self._reduce_helper(
                      start, mid, 2 * node, node_start, mid
                  ),
                  self._reduce_helper(
                      mid + 1, end, 2 * node + 1, mid + 1, node_end
                  ),
              )
  
imports: import argparse
  import operator
  import os
  import random
  import time
  import gym
  import matplotlib.pyplot
  import numpy
  import tensorflow
  import tensorlayer
label_desc: Use image node_id 2 for calling the SegmentTree obj's underlying member method code with example usage: obj._reduce_helper(start, end, node, node_start, node_end) and returns: self, self, self, self