# File lib/validates_timeliness/formats.rb, line 230
      def add_formats(type, *add_formats)
        formats = self.send("#{type}_formats")
        options = {}
        options = add_formats.pop if add_formats.last.is_a?(Hash)
        before = options[:before]
        raise "Format for :before option #{format} was not found." if before && !formats.include?(before)

        add_formats.each do |format|
          raise "Format #{format} is already included in #{type} formats" if formats.include?(format)

          index = before ? formats.index(before) : -1
          formats.insert(index, format)
        end
        compile_format_expressions
      end