code: def _img_4d_mni(shape=_shape_4d_default(), affine=_affine_mni()):
      return Nifti1Image(_rng().uniform(size=shape), affine=affine)
  
imports: import warnings
  import nibabel
  import numpy
  import pytest
  from nibabel import Nifti1Image
  from nilearn import image
  from nilearn.datasets.tests._testing import request_mocker
  from nilearn.datasets.tests._testing import temp_nilearn_data_dir
  from nilearn.experimental.surface.tests.conftest import make_mini_img, mini_img, mini_mesh
label_desc: Use image node_id 29 for calling a global function with example usage: _img_4d_mni(shape, affine) and returns: Nifti1Image