There are lots of other modules
https://metacpan.org/module/Method::Signatures https://metacpan.org/module/MooseX::Method::Signatures https://metacpan.org/module/Method::Signatures::Simple
and many more. In this case, there might be too many ways to do it.
There are other modules out there like this, including one that bakes it into Moose methods. This also highlights a cool Perl feature: hack able syntax.