rescue在方法中不需要绑定到显式的begin，这就是定义语法的方式.有关示例，请参见此处#19 和上面的骗子.

rescues do not need to be tied to an explicit begin when they're in a method, that's just the way the syntax is defined. For examples, see #19 here and this SO question, as well as the dupe above.