code: def load_datasets(self):
      self.train_dataset = MultiDatasetLoader("train")
      self.val_dataset = MultiDatasetLoader("val")
      self.test_dataset = MultiDatasetLoader("test")
  
      self.train_dataset.load(self.config)
      self.val_dataset.load(self.config)
      self.test_dataset.load(self.config)
  
      # If number of datasets is one, this will return the first loader
      self.train_loader = self.train_dataset
      self.val_loader = self.val_dataset
      self.test_loader = self.test_dataset
  
      self.mapping = {
          "train": self.train_dataset,
          "val": self.val_dataset,
          "test": self.test_dataset,
      }
  
      self.test_reporter = None
      self.should_not_log = self.config.training.should_not_log
  
file_path: mmf/mmf/common/dataset_loader.py
imports: import warnings
  from mmf.common.sample import SampleList
  from mmf.datasets.multi_dataset_loader import MultiDatasetLoader
  from mmf.utils.build import build_multiple_datamodules, build_test_reporter
label_desc: Use image node_id 2 for calling the DatasetLoader obj's underlying member method code with example usage: obj.load_datasets() without return types