code: def _get_parser():
      """Return command-line argument parser."""
      p = argparse.ArgumentParser(description=__doc__)
      p.add_argument(
          "infile", help="Neuroimaging volume to compute statistics on."
      )
      p.add_argument(
          "-V",
          "--Volume",
          action="store_true",
          required=False,
          help="Compute mask volume of a given mask image.",
      )
      p.add_argument(
          "--units",
          default="mm3",
          required=False,
          choices=("mm3", "vox"),
          help="Preferred output units",
      )
      return p
  
imports: import argparse
  from nibabel.imagestats import count_nonzero_voxels, mask_volume
  from nibabel.loadsave import load
label_desc: Use image node_id 1 for calling a global function with example usage: _get_parser() and returns: p