code: def test_add_markers_cut_coords_is_none():
      """Tests a special case for ``add_markers`` when ``cut_coords`` are None.
      This case is used when coords are placed on glass brain.
      """
      orthoslicer = OrthoSlicer(cut_coords=(None, None, None))
      orthoslicer.add_markers([(0, 0, 2)])
      orthoslicer.close()
  
imports: import matplotlib
  import matplotlib.pyplot
  import numpy
  import pytest
  from nibabel import Nifti1Image
  from nilearn.datasets import load_mni152_template
  from nilearn.plotting.displays import BaseAxes, LProjector, LRProjector, LYRProjector, LYRZProjector, LZRProjector, LZRYProjector, MosaicSlicer, OrthoProjector, OrthoSlicer, RProjector, TiledSlicer, XProjector, XSlicer, XZProjector, XZSlicer, YProjector, YSlicer, YXProjector, YXSlicer, YZProjector, YZSlicer, ZProjector, ZSlicer
label_desc: Use image node_id 20 for calling a global function with example usage: test_add_markers_cut_coords_is_none() without return types