code: def test_content(self):
      test_image = nib.Nifti1Image(
          np.random.randint(0, 2, size=[128, 128, 128]).astype(float),
          np.eye(4),
      )
      with tempfile.TemporaryDirectory() as tempdir:
          nib.save(
              test_image, os.path.join(tempdir, "test_image1.nii.gz")
          )
          nib.save(
              test_image, os.path.join(tempdir, "test_label1.nii.gz")
          )
          nib.save(
              test_image, os.path.join(tempdir, "test_extra1.nii.gz")
          )
          nib.save(
              test_image, os.path.join(tempdir, "test_image2.nii.gz")
          )
  
          datalist = [
              {
                  "image": os.path.join(tempdir, "test_image1.nii.gz"),
                  "label": [
                      os.path.join(tempdir, "test_label1.nii.gz"),
                      os.path.join(tempdir, "test_extra1.nii.gz"),
                  ],
              },
              {
                  "image": Path(
                      os.path.join(tempdir, "test_image2.nii.gz")
                  ),
                  "label": Path(
                      os.path.join(tempdir, "test_label_missing.nii.gz")
                  ),
              },
          ]
  
          missings = check_missing_files(
              datalist=datalist, keys=["image", "label"]
          )
          self.assertEqual(len(missings), 1)
          self.assertEqual(
              str(missings[0]),
              os.path.join(tempdir, "test_label_missing.nii.gz"),
          )
  
          # test with missing key and relative path
          datalist = [
              {
                  "image": "test_image1.nii.gz",
                  "label": "test_label_missing.nii.gz",
              }
          ]
          missings = check_missing_files(
              datalist=datalist,
              keys=["image", "label", "test"],
              root_dir=tempdir,
              allow_missing_keys=True,
          )
          self.assertEqual(
              f"{missings[0]}",
              os.path.join(tempdir, "test_label_missing.nii.gz"),
          )
  
file_path: MONAI/tests/test_check_missing_files.py
imports: from __future__ import annotations
  import os
  import tempfile
  import unittest
  from pathlib import Path
  import nibabel
  import numpy
  from monai.data import check_missing_files
label_desc: Use image node_id 1 for calling the TestCheckMissingFiles obj's underlying member method code with example usage: obj.test_content() without return types