diff --git a/agaric/templates/block/block.html.twig b/agaric/templates/block/block.html.twig
index e5b4378..7a5788a 100644
--- a/agaric/templates/block/block.html.twig
+++ b/agaric/templates/block/block.html.twig
@@ -25,7 +25,7 @@
  * @see template_preprocess_block()
  */
 #}
-<section {{ attributes }}.addClass('section'>
+<section {{ attributes.addClass('section') }}>
   <div class="container">
     <div class="frow content">
       <div class="flow_full">