Sure! First look through what functions are available and try to find one you could add. Then go ahead and open a pull request to add it!

I'm not really sure.. what do you mean by look through what functions are available and try to find one I could add, should I modify the one that are already in src? or should I make another different function?

Make another one :)

I'm not sure how to make a new one, earlier I'm looking in the issues if there is something I can help with, but it seems the issues open are not update anymore, and if I make a new issue or function, do I need to make my own test in the test folder as well? I'm sorry I'm not what should I do.

Follow the same process that I show in the course, just with a different function. So yes, you'll need to open your own issue with your own suggestion of a function, then when I accept the idea, you can make a pull request that includes the function and tests for it.

Good luck!