如何理解以下文字？ -Attaching an assertion to a checkpoint means that we believe that whenever execution reaches the point in question, in any execution of the algorithm on any legal input,the assertion will be true.如何理解以下文字？ ◼ Attaching an assertion to a checkpoint means that we believe that whenever execution reaches the point in question, in any execution of the algorithm on any legal input, the assertion will be true