code: def test_interpolate_zmap() -> None:
      contour_point_num = 2
      zmap = {(0, 0): 1.0, (1, 1): 4.0}
      expected = np.array([[1.0, 2.5], [2.5, 4.0]])
  
      actual = _interpolate_zmap(zmap, contour_point_num)
  
      assert np.allclose(expected, actual)
  
imports: import numpy
  from optuna.visualization.matplotlib._contour import _create_zmap
  from optuna.visualization.matplotlib._contour import _interpolate_zmap
label_desc: Use image node_id 2 for calling a global function with example usage: test_interpolate_zmap() without return types