Python regular expression

I want to ask ,
problem 1:
' MR_SHOP mr_shop' Why are you using serach() Method , The return value is MR_SHOP Is the return value a string ? emm In my submission ' The content is a string ' According to the result, is a new string returned ?'
problem 2：
Returns for the first time a tuple of span(0,7) Why should we include spaces ? Is to take the index of the space as the end value ?
![img](https://img-mid.csdnimg.cn/release/static/image/mid/ask/61841

What are you asking about , I can't understand . The returned object is not a string . A space is also a length , But here mr_shop Not just 7 Well Where does the space end