code: def test_cvxpy_1x6_to_3x3():
      """Test conversion from Voigt notation."""
      if have_cvxpy:
          V = np.arange(1, 7)[:, np.newaxis].astype(float)
          T = np.array(
              (
                  [1, 4.24264069, 3.53553391],
                  [4.24264069, 2, 2.82842712],
                  [3.53553391, 2.82842712, 3],
              )
          )
          npt.assert_array_almost_equal(
              qti.cvxpy_1x6_to_3x3(V).value, T
          )
          npt.assert_array_almost_equal(
              qti.cvxpy_1x6_to_3x3(qti.from_3x3_to_6x1(T)).value, T
          )
  
imports: import numpy
  import numpy.testing
  import dipy.reconst.qti
  from dipy.core.gradients import gradient_table
  from dipy.sims.voxel import vec2vec_rotmat
  from dipy.core.sphere import disperse_charges, HemiSphere
  from dipy.reconst.dti import fractional_anisotropy
  from dipy.testing.decorators import set_random_number_generator
  from dipy.utils.optpkg import optional_package
label_desc: Use image node_id 5 for calling a global function with example usage: test_cvxpy_1x6_to_3x3() without return types