code: def masked_multi_subject_data(masked_images):
      return np.stack(masked_images, axis=-1)
  
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 1 for calling a global function with example usage: masked_multi_subject_data(masked_images) and returns: np