Return untainted value

[merkys]

First, thanks for this module. I have noticed that most of the modules under Data::Validate:: namespace use the same convention for their return values. If the validated value is valid, they return the untainted value, otherwise undef. Data::Validate::UUID differs from this convention by returning truthy/falsey. Would it be possible to change the API to match the others under Data::Validate::? Note that the change would be backwards compatible, as any valid UUID matches truthy and undef matches falsey.