# File lib/active_record/validations.rb, line 821
      def validates_inclusion_of(*attr_names)
        configuration = { :on => :save }
        configuration.update(attr_names.extract_options!)

        enum = configuration[:in] || configuration[:within]

        raise(ArgumentError, "An object with the method include? is required must be supplied as the :in option of the configuration hash") unless enum.respond_to?(:include?)

        validates_each(attr_names, configuration) do |record, attr_name, value|
          unless enum.include?(value)
            record.errors.add(attr_name, :inclusion, :default => configuration[:message], :value => value) 
          end
        end
      end