def render(document)
      document['content'].each_with_object([]) do |node, result|
        result << find_renderer(node).render(node)
      end.join("\n")
    end
def render(document)
      document['content'].each_with_object([]) do |node, result|
        result << find_renderer(node).render(node)
      end.join("\n")
    end
Renders all nodes in the document.