. . .is still going to break if someone passes a reference argument that isn't an instance of the class.

At least it will break in the same way that it used to break if someone passed a reference. Unless, of course, that reference isn't a hash reference. Or even if it is a hash reference, it is running with warnings enabled and the referenced hash doesn't have a class key...

*shiver*

-sauoq
"My two cents aren't worth a dime.";