Imagine I need to check if in

```
longString = "this is a long sting where a lo must be detected."

```

the substring `lo` as a word is contained. I need to use the leading and trailing whitespace to detect it like `" lo "`. How do I do this?  

(To complicate matters the search string comes from a list of strings like `[' lo ','bar']`.I know the solution [without whitespaces like this.](https://stackoverflow.com/questions/3389574/check-if-multiple-strings-exist-in-another-string) )