code: def __getitem__(self, idx):
      assert 0 <= idx < self._capacity
      return self._value[self._capacity + idx]
  
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 5 for calling the SegmentTree obj's underlying member method code with example usage: obj.__getitem__(idx) and returns: self