def render_children
      children = ''

      list_item.children.each do |child|
        children += self.class.render(child, opts)
      end

      children
    end
def render_children
      children = ''

      list_item.children.each do |child|
        children += self.class.render(child, opts)
      end

      children
    end
Loop over all list item children calling render on each

 @return [String] compiled string of all the rendered list item children