code: def test_round_robin_strategy(self):
      dataloaders = self._build_dataloaders()
      strategy = (
          iteration_strategies.RoundRobinIterationStrategy.from_params(
              dataloaders=dataloaders
          )
      )
  
      counter = Counter()
      count = 100
      for _ in range(count):
          counter[strategy()] += 1
  
      for idx in range(0, self.NUM_DATALOADERS):
          self.assertEqual(counter[idx], count // self.NUM_DATALOADERS)
  
      strategy = (
          iteration_strategies.RoundRobinIterationStrategy.from_params(
              dataloaders=dataloaders, start_idx=2
          )
      )
      counter = Counter()
      count = 100
      for _ in range(count):
          counter[strategy()] += 1
  
      for idx in range(0, self.NUM_DATALOADERS):
          self.assertEqual(counter[idx], count // self.NUM_DATALOADERS)
  
file_path: mmf/tests/datasets/test_iteration_strategies.py
imports: import unittest
  from collections import Counter
  import numpy
  import torch
  from mmf.datasets import iteration_strategies
  from tests.test_utils import NumbersDataset
label_desc: Use image node_id 4 for calling the TestIterationStrategies obj's underlying member method code with example usage: obj.test_round_robin_strategy() without return types