An alternative method to accomplish the same result would test whether the current item in the tuple is even (using if not num % 2:) and, if true, would add the current item to the running total.
实现相同结果的另一种方法是测试tuple中的当前项是否是偶数(使用if not num % 2：)，如果为真，那么将当前项添加到运行总和中。
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If I'm inside this FOR, OK, and I'm running around, if I ever hit a place where this test is true, I'm going to execute that return, return that return returns from the entire procedure.