code: def test_improper_Contrast_inputs(effect, variance, match):
      with pytest.raises(ValueError, match=match):
          Contrast(effect, variance, stat_type="t")
  
imports: import numpy
  import pytest
  import scipy.stats
  from numpy.testing import assert_almost_equal
  from sklearn.datasets import make_regression
  from sklearn.linear_model import LinearRegression
  from nilearn.glm.contrasts import Contrast, _compute_fixed_effects_params, compute_contrast, compute_fixed_effect_contrast, expression_to_contrast_vector
  from nilearn.glm.first_level import run_glm
label_desc: Use image node_id 16 for calling a global function with example usage: test_improper_Contrast_inputs(effect, variance, match) without return types