private void ParseLineGroup(
            ParseInput input
            )
        {
            ParseResult result;

            if (MarkdownHeading.CanParseFrom(input))
            {
                result = MarkdownHeading.ParseFrom(input);
            }
            else if (MarkdownHorizontalRule.CanParseFrom(input))
            {
                result = MarkdownHorizontalRule.ParseFrom(input);
            }
            else if (MarkdownQuote.CanParseFrom(input))
            {
                result = MarkdownQuote.ParseFrom(input);
            }
            else if (MarkdownList.CanParseFrom(input))
            {
                result = MarkdownList.ParseFrom(input);
            }
            else
            {
                result = MarkdownParagraph.ParseFrom(input);
            }
            foreach (IHtmlable entry in result.GetContent())
            {
                Content.AddLast(entry);
            }
        }