If the function doesn't exist, don't do anything. aCoolFunction is false so the other half of the statement won't execute. If it does exist, call it. Useless as

If the function doesn't exist, don't do anything. aCoolFunction is false so the other half of the statement won't execute. If it does exist, call it. Useless as written, but there may be cases where you don't know if it is defined or not when you want to call it.