code: def test_dummy_regressor():
      """Test function for DummyRegressor."""
      X_train, y_train = load_unit_test(
          split="train", return_type="numpy3D"
      )
      X_test, _ = load_unit_test(split="test", return_type="numpy3D")
      dummy = DummyRegressor()
      dummy.fit(X_train, y_train)
      pred = dummy.predict(X_test)
      assert (pred == 1.5).all()
  
label_desc: Use image node_id 1 for calling a global function with example usage: test_dummy_regressor() without return types