if you do something wrong, it does kick back python errors, though.  it's not as if there's a fancy gui alert to tell you what's gone wrong (not that there should be, i'm not sure how it would even work that way).  so if you run it and you get an error, you just need to change something.   the error should tell you what went wrong and where (what file, what line). 

that said, errors shouldn't break anything, so don't fear them, either.  basically, matmatic works perfectly, but that doesn't mean you'll never encounter errors.