code: def add_dataset_type(df: DataFrame, dataset_type):
      assert dataset_type in [
          TRAIN_SET,
          VALIDATE_SET,
          TEST_SET,
      ], f"dataset_type must be one of {TRAIN_SET}, {VALIDATE_SET}, {TEST_SET}"
      df[TYPE] = dataset_type
      return df
  
label_desc: Use image node_id 2 for calling a global function with example usage: add_dataset_type(df, dataset_type) and returns: df