def METHOD_NAME():
    X, y = boston_housing_data()
    X_train, X_test, y_train, y_test = train_test_split(
        X, y, test_size=0.3, random_state=123, shuffle=True
    )
    tree = DecisionTreeRegressor(random_state=123)
    bag = BaggingRegressor(base_estimator=tree, n_estimators=10, random_state=123)
    avg_expected_loss, avg_bias, avg_var = bias_variance_decomp(
        bag, X_train, y_train, X_test, y_test, loss="mse", random_seed=123
    )
    assert round(avg_expected_loss, 2) == 20.24, avg_expected_loss
    assert round(avg_bias, 2) == 15.63, avg_bias
    assert round(avg_var, 2) == 4.61, avg_var