whitespace in org source files

[excalamus]

I'm hacking on ob-shell.el and I see that the source has mixed tabs and spaces. 
If I were to contribute changes, would it be an issue if tabs were converted to 
whitespace?

I've not used the email contribution style before and have had whitespace 
issues in the past with GitHub PRs.   I typically run whitespace-cleanup with 
the before-save-hook which changes tabs to spaces.