# File lib/markaby/builder_tags.rb, line 18
    def html_tag(sym, *args, &block)
      if @auto_validation && @tagset.self_closing.include?(sym) && block
        raise InvalidXhtmlError, "the `#{sym}' element is self-closing, please remove the block"
      elsif args.empty? && !block
        CssProxy.new(self, @streams.last, sym)
      else
        tag!(sym, *args, &block)
      end
    end