code: def teardown_module():
      global gtab1, gtab2, gtab, DTDs, S0
      gtab1, gtab2, gtab, DTDs, S0 = None, None, None, None, None
  
imports: import numpy
  import math
  from dipy.core.sphere import disperse_charges, HemiSphere
  from dipy.reconst.utils import cti_design_matrix
  from numpy.testing import assert_array_almost_equal, assert_raises
  from dipy.reconst.tests.test_qti import _anisotropic_DTD, _isotropic_DTD
  from dipy.core.gradients import gradient_table
  import dipy.reconst.qti
  import dipy.reconst.cti
  from dipy.reconst.dti import decompose_tensor, mean_diffusivity
  from dipy.reconst.cti import split_cti_params, ls_fit_cti, multi_gaussian_k_from_c, from_qte_to_cti
  from dipy.reconst.dki import mean_kurtosis, axial_kurtosis, radial_kurtosis, mean_kurtosis_tensor, kurtosis_fractional_anisotropy
label_desc: Use image node_id 2 for calling a global function with example usage: teardown_module() without return types