If the gauntlet condition is something that would prevent the function from succeeding, it returns an error immediately. If the gauntlet condition can be handled, I do so before entering the main body of code whenever possible. I am primarily trying to avoid nested IF statements, which in my experience are one of the primary causes of obscure and hard to debug coding errors.

Would some of the downvoters mind explaining your downvotes? It seems rude to downvote without an explanation.

If a string is known to have no value, then the value should be an empty string, not a null string.