code: def _img_3d_ones(shape=_shape_3d_default(), affine=_affine_eye()):
      """Return a ones-filled 3D Nifti1Image (identity affine).
  
      Mostly used for set up in other fixtures in other testing modules.
      """
      return _img_ones(shape, 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 25 for calling a global function with example usage: _img_3d_ones(shape, affine) and returns: _img_ones