Is there anyway to avoid a function call if function returns `None`?
I'm doing this at the moment, but it seems very inefficient calling the function twice

```
if  bool(runChecks(problems)):
    return  runChecks(problems)

```

I would rather do this in one line of code, instead of calling it twice. If it returns `True`, then it returns a string with the error.

If it returns false, then it continues with the rest of the program. The runChecks() is a function that makes sure input is viable for program. no letters or chars that I havnt programmed it for