code: def test_itk_dicom_series_reader(self):
      filenames = "tests/testing_data/CT_DICOM"
      itk.ProcessObject.SetGlobalWarningDisplay(False)
      result = LoadImage(
          image_only=True, reader=ITKReader(pixel_type=itk.UC)
      )(filenames)
      result = EnsureChannelFirst()(result)
      self.assertEqual(result.shape[0], 1)
  
file_path: MONAI/tests/test_ensure_channel_first.py
imports: from __future__ import annotations
  import os
  import tempfile
  import unittest
  import nibabel
  import numpy
  import torch
  from parameterized import parameterized
  from PIL import Image
  from monai.data.meta_tensor import MetaTensor
  from monai.transforms import EnsureChannelFirst, LoadImage
  from monai.utils import optional_import
label_desc: Use image node_id 2 for calling the TestEnsureChannelFirst obj's underlying member method code with example usage: obj.test_itk_dicom_series_reader() without return types