Keep all validations inside a single ActiveModel::Validator class

Rails
1

Hi!

I plan to use ActiveModel::Validator to validate a plain Ruby class, but
I have intention to keep all validations outside the original class,
while using PresenceValidator and FormatValidator, default on Rails.
Something like this:

payer.rb

module MyMoip
class Payer
include ActiveModel::Validations

attr_accessor :id, :name, :email,
              :address_street, :address_street_number,

:address_street_extra,
:address_neighbourhood, :address_city, :address_state,
:address_country, :address_cep, :address_phone

validates_with Validators::PayerValidator

end
end

payer_validator.rb

module MyMoip
module Validators
class PayerValidator < ActiveModel::Validator

  validate :id, presence: true

  def validate(record)
    # more complex validations
  end
end

end
end

It is possible?