# File lib/active_record/attribute_methods/deprecated_underscore_read.rb, line 23
      def _attribute(attr_name)
        ActiveSupport::Deprecation.warn(
          "You have called '_#{attr_name}'. This is deprecated. Please use " \
          "either '#{attr_name}' or read_attribute('#{attr_name}')."
        )
        read_attribute(attr_name)
      end