current_url = self.config.start_url
Фото: Hannah Mckay / Reuters
，更多细节参见91视频
// Define the side effect, but don't run it yet
话音落下没多久，阿爸就笑嘻嘻地回了屋。
`@receiver isNil ifTrue: `@nilBlock -> `@receiver ifNil: `@nilBlockIn fact, both versions work—but they apply different filters to the target node. Try to remember which one.