code: def _test_actual_length(self, loader):
      counter = 0
      for batch in loader:
          counter += 1
      self.assertEqual(counter, self._length)
  
file_path: avalanche/tests/benchmarks/utils/test_replay_loader.py
imports: import unittest
  import numpy
  from avalanche.benchmarks.classic import SplitMNIST
  from avalanche.benchmarks.utils.data_loader import ReplayDataLoader
label_desc: Use image node_id 5 for calling the TestReplayDataLoader obj's underlying member method code with example usage: obj._test_actual_length(loader) without return types