What's the meaning of complete whole?

Hi, I teach English in my country and I've come across a collocation I just can't understand, I was reading an explanation for a sentence in the simple present (the sentence was "Peter comes from Spain") it's explained that the action in the sentence is seen as a complete whole. What does the writer mean? Isn't it correct if he just says "the action is completed" for example? What difference does it make to use whole?