require 'open_food_network/last_used_address' class Api::Admin::UserSerializer < ActiveModel::Serializer attributes :id, :email has_one :ship_address, serializer: Api::AddressSerializer has_one :bill_address, serializer: Api::AddressSerializer def ship_address object.ship_address || OpenFoodNetwork::LastUsedAddress.new(object.email).last_used_ship_address end def bill_address object.bill_address || OpenFoodNetwork::LastUsedAddress.new(object.email).last_used_bill_address end end