Topic: Extract all validations to a single ActiveModel::Validator class

I am using ActiveModel::Validations to a plain Ruby class and I plan to use ActiveModel valitions' DSL inside a ActiveModel::Validator inherited class. It is possible?

# Payer
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

# PayerValidator
module MyMoip
  module Validators
    class PayerValidator < ActiveModel::Validator

      validate :id, presence: true

      def validate(record)
        # more complex validations
      end
    end
  end
end