AttributeError：“ RandomForestRegressor”对象没有属性“ _validate_data”是什么意思？

Question

from sklearn.ensemble import RandomForestRegressor

regressor = RandomForestRegressor(n_estimators=20, random_state=0)

regressor.fit(x_train, y_train)

y_pred = regressor.predict(x_test)

AttributeError：“ RandomForestRegressor”对象没有属性“ _validate_data”