code: def test_append_and_sample(self):
      capacity = self.capacity
      num_steps = self.num_steps
      rbuf = replay_buffer.PrioritizedReplayBuffer(
          capacity,
          normalize_by_max=self.normalize_by_max,
          error_max=5,
          num_steps=num_steps,
      )
  
      self.assertEqual(len(rbuf), 0)
  
      # Add one and sample one
      correct_item = collections.deque([], maxlen=num_steps)
      for _ in range(num_steps):
          trans1 = dict(
              state=0,
              action=1,
              reward=2,
              next_state=3,
              next_action=4,
              is_state_terminal=False,
          )
          correct_item.append(trans1)
          rbuf.append(**trans1)
      self.assertEqual(len(rbuf), 1)
      s1 = rbuf.sample(1)
      rbuf.update_errors([3.14])
      self.assertEqual(len(s1), 1)
      self.assertAlmostEqual(s1[0][0]["weight"], 1.0)
      del s1[0][0]["weight"]
      self.assertEqual(s1[0], list(correct_item))
  
      # Add two and sample two, which must be unique
      correct_item2 = copy.deepcopy(correct_item)
      trans2 = dict(
          state=1,
          action=1,
          reward=2,
          next_state=3,
          next_action=4,
          is_state_terminal=True,
      )
      correct_item2.append(trans2)
      rbuf.append(**trans2)
      self.assertEqual(len(rbuf), 2)
      s2 = rbuf.sample(2)
      rbuf.update_errors([3.14, 2.71])
      self.assertEqual(len(s2), 2)
      del s2[0][0]["weight"]
      del s2[1][0]["weight"]
      if s2[0][num_steps - 1]["state"] == 1:
          self.assertEqual(s2[0], list(correct_item2))
          self.assertEqual(s2[1], list(correct_item))
      else:
          self.assertEqual(s2[0], list(correct_item))
          self.assertEqual(s2[1], list(correct_item2))
  
      # Weights should be different for different TD-errors
      s3 = rbuf.sample(2)
      self.assertNotAlmostEqual(s3[0][0]["weight"], s3[1][0]["weight"])
  
      # Weights should be equal for different but clipped TD-errors
      rbuf.update_errors([5, 10])
      s3 = rbuf.sample(2)
      self.assertAlmostEqual(s3[0][0]["weight"], s3[1][0]["weight"])
  
      # Weights should be equal for the same TD-errors
      rbuf.update_errors([3.14, 3.14])
      s4 = rbuf.sample(2)
      self.assertAlmostEqual(s4[0][0]["weight"], s4[1][0]["weight"])
  
imports: import collections
  import copy
  import os
  import tempfile
  import unittest
  from chainer import testing
  import numpy
  from chainerrl import replay_buffer
label_desc: Use image node_id 1 for calling the TestPrioritizedReplayBuffer obj's underlying member method code with example usage: obj.test_append_and_sample() without return types