code: def test_mask():
      """
      Test whether setting incorrect mask raises and error
      """
      mask_correct = data_multi[..., 0] > 0.2
      mask_not_correct = np.array(
          [[False, True, False], [True, False]], dtype=object
      )
  
      ivim_fit = ivim_model_trr.fit(data_multi, mask_correct)
      est_signal = ivim_fit.predict(gtab, S0=1.0)
      assert_array_equal(est_signal.shape, data_multi.shape)
      assert_array_almost_equal(est_signal, data_multi)
      assert_array_almost_equal(ivim_fit.model_params, ivim_params_trr)
      assert_raises(
          ValueError,
          ivim_model_trr.fit,
          data_multi,
          mask=mask_not_correct,
      )
  
imports: import warnings
  import numpy
  from numpy.testing import assert_array_equal, assert_array_almost_equal, assert_raises, assert_array_less, assert_, assert_equal
  from dipy.testing import assert_greater_equal
  import pytest
  from dipy.reconst.ivim import ivim_prediction, IvimModel
  from dipy.core.gradients import gradient_table, generate_bvecs
  from dipy.sims.voxel import multi_tensor
  from dipy.utils.optpkg import optional_package
label_desc: Use image node_id 6 for calling a global function with example usage: test_mask() without return types