Nothing surprising about a method that does not take params, if the method always returns the same thing. For a method that does not always return the same thing (not a good idea anyway), not providing a way for the caller to specify what is wanted via a param seems solidly in the realm of misplaced optimization.

You asked for suggestions on how to design for your need. My experience has shown me that clarity, simplicity and consistency are above all. So I shared my suggestion. I'm not interested in debating things like "should I have a type constraint that only warns on a bad value" or "should I have a method return one of three things but take no parameters," to be honest. Those questions are long settled, in my view. While TIMTOWTDI is still true, there's usually a standard way to do most basic programming tasks in Perl, these days, or at least some standard ways to *not* do them.