How to create custom type with parameter

I have such construction

Types::String.default { [SecureRandom.hex(12), suffix].join.freeze }

I wanted to create such custom type, I came up with this:

HexDefault =
   Dry.Types.Constructor(Types::String) do |suffix|
     [SecureRandom.hex(12), suffix].join.freeze

and using like this

attribute :uid, Types::HexDefult[suffix]

but it generates the hex right way, it doesn’t create a callable object

It would be

HexDefault = proc do |suffix|
  Types::String.default { "#{SecureRandom.hex(12)}#{suffix}".freeze }

attribute :uid, Types::HexDefult["hello"]

this is great, thanks!