class_docstr: Class to store the anat array in cache, to avoid reloading it
  each time.
code: def get_anat(cls):
      filename = find_mni_template()
      if cls.anat is None:
          if filename is None:
              raise OSError(
                  "Cannot find template file T1_brain.nii.gz "
                  "required to plot anatomy, see the nipy documentation "
                  "installaton section for how to install template files."
              )
          anat_im = load(filename)
          anat = anat_im.get_fdata()
          anat = anat.astype(np.float64)
          anat_mask = ndimage.morphology.binary_fill_holes(anat > 0)
          anat = np.ma.masked_array(anat, np.logical_not(anat_mask))
          cls.anat_sform = get_affine(anat_im)
          cls.anat = anat
          cls.anat_max = anat.max()
      return cls.anat, cls.anat_sform, cls.anat_max
  
file_path: nipy/nipy/labs/viz_tools/anat_cache.py
imports: import os
  import numpy
  from nibabel import load
  from scipy import ndimage
  from nipy.io.nibcompat import get_affine
label_desc: Use image node_id 1 for calling the _AnatCache obj's underlying member method code with example usage: obj.get_anat(cls) and returns: cls,  cls,  cls