class Kramdown::Parser::Kramdown

def parse_codeblock_fenced
  if @src.check(self.class::FENCED_CODEBLOCK_MATCH)
    start_line_number = @src.current_line_number
    @src.pos += @src.matched_size
    el = new_block_el(:codeblock, @src[5], nil, :location => start_line_number)
    lang = @src[3].to_s.strip
    unless lang.empty?
      el.options[:lang] = lang
      el.attr['class'] = "language-#{@src[4]}"
    end
    @tree.children << el
    true
  else
    false
  end
end