code: def test_iterable_map(self):
      dsets = self._create_dummy_iterable_dataset_dict()
      fn_kwargs = {"n": 3}
      mapped_dsets: IterableDatasetDict = dsets.map(
          lambda x, n: {"foo": [n] * len(x["filename"])},
          batched=True,
          fn_kwargs=fn_kwargs,
      )
      mapped_example = next(iter(mapped_dsets["train"]))
      self.assertListEqual(
          sorted(mapped_example.keys()), sorted(["filename", "foo"])
      )
      self.assertLessEqual(mapped_example["foo"], 3)
      del dsets, mapped_dsets
  
imports: import os
  import tempfile
  from unittest import TestCase
  import numpy
  import pandas
  import pytest
  from datasets import load_from_disk
  from datasets.arrow_dataset import Dataset
  from datasets.dataset_dict import DatasetDict, IterableDatasetDict
  from datasets.features import ClassLabel, Features, Sequence, Value
  from datasets.iterable_dataset import IterableDataset
  from datasets.splits import NamedSplit
  from .utils import assert_arrow_memory_doesnt_increase, assert_arrow_memory_increases, require_tf, require_torch
label_desc: Use image node_id 18 for calling the DatasetDictTest obj's underlying member method code with example usage: obj.test_iterable_map() without return types