class_docstr: Base class for defining iteration strategies that will be used
  for iterating over multiple datasets during multitasking.
  
  An IterationStrategy implementation should `__call__` method
  which returns index of dataset from which next batch must be
  pulled.
  
  Class can also define `should_exhaust_all_iterators` property
  which defines whether all iterators should be exhausted before
  reigniting next batch of iterators. For example, in size
  proportional iteration strategy, all iterators must be finished
  before starting a new round so that all of them get equal
  opportunity to present themselves according to their size.
  
  Args:
      config (Config): Object of type Config which should be defined
          for each iteration strategy for configurable parameters.
      dataloaders (Dict[str, DataLoader]): A dictionary containing
          mapping from dataset key to its dataloader.
  
  Usage::
  
      from dataclasses import dataclass
      from mmf.common.registry import registry
      from mmf.datasets.iterators import IterationStrategy
  
  
      @registry.register_iteration_strategy("my_iteration_strategy")
      class MyStrategy(IterationStrategy):
          @dataclass
          class Config:
              name: str = "my_strategy"
          def __init__(self, config, dataloader):
              ...
code: def __init__(
      self,
      config: Config,
      dataloaders: Dict[str, DataLoader],
      *args,
      **kwargs,
  ):
      config = OmegaConf.merge(
          OmegaConf.structured(self.Config), config
      )
      self.config = config
      self.dataloaders = dataloaders
  
imports: import logging
  import warnings
  from dataclasses import dataclass
  from typing import Dict
  import numpy
  from mmf.common.registry import registry
  from mmf.utils.configuration import get_global_config
  from mmf.utils.dataset import dataset_list_from_config
  from omegaconf import MISSING, OmegaConf
  from torch.utils.data import DataLoader
label_desc: Use image node_id 1 to create a new IterationStrategy object  with example: obj = IterationStrategy(config, dataloaders)