code: def mask() -> np.ndarray:
      return np.array(
          [
              [[0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0]],
              [[0, 0, 0, 0], [0, 1, 1, 0], [0, 1, 1, 0], [0, 0, 0, 0]],
              [[0, 0, 0, 0], [0, 1, 1, 0], [0, 1, 1, 0], [0, 0, 0, 0]],
              [[0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0]],
          ],
          dtype=bool,
      )
  
imports: from typing import Iterable, Sequence
  import numpy
  import pytest
  from nibabel.nifti1 import Nifti1Pair
  from nibabel.spatialimages import SpatialImage
  from brainiak.image import mask_image, mask_images, MaskedMultiSubjectData, multimask_images, SingleConditionSpec
label_desc: Use image node_id 4 for calling a global function with example usage: mask() and returns: np