    # File lib/active_record/validations.rb, line 160
        def add(attribute, message = nil, options = {})
          options[:message] = options.delete(:default) if options[:default].is_a?(Symbol)
          error, message = message, nil if message.is_a?(Error)

          @errors[attribute.to_s] ||= []
          @errors[attribute.to_s] << (error || Error.new(@base, attribute, message, options))
        end