code: def test_unpack_var(self):
      for var in self.vars:
          with pytest.raises(self.module.AFNIHeaderError):
              self.module._unpack_var(var)
  
file_path: nibabel/nibabel/tests/test_brikhead.py
imports: from os.path import join
  import numpy
  import pytest
  from numpy.testing import assert_array_equal
  from ..None import Nifti1Image, brikhead, load
  from ..testing import assert_data_similar, data_path
  from .test_fileslice import slicer_samples
label_desc: Use image node_id 1 for calling the TestBadVars obj's underlying member method code with example usage: obj.test_unpack_var() without return types