Init estimation for regression. (#8272)

tests/python/test_with_shap.py

@@ -9,6 +9,7 @@ except Exception:
     shap = None
     pass
 
+
 pytestmark = pytest.mark.skipif(shap is None, reason="Requires shap package")
 
 
@@ -16,11 +17,16 @@ pytestmark = pytest.mark.skipif(shap is None, reason="Requires shap package")
 # Changes in binary format may cause problems
 def test_with_shap():
     from sklearn.datasets import fetch_california_housing
+
     X, y = fetch_california_housing(return_X_y=True)
     dtrain = xgb.DMatrix(X, label=y)
     model = xgb.train({"learning_rate": 0.01}, dtrain, 10)
     explainer = shap.TreeExplainer(model)
     shap_values = explainer.shap_values(X)
     margin = model.predict(dtrain, output_margin=True)
-    assert np.allclose(np.sum(shap_values, axis=len(shap_values.shape) - 1),
-                       margin - explainer.expected_value, 1e-3, 1e-3)
+    assert np.allclose(
+        np.sum(shap_values, axis=len(shap_values.shape) - 1),
+        margin - explainer.expected_value,
+        1e-3,
+        1e-3,
+    )