1 files changed, 2 insertions, 0 deletions
diff --git a/index.js b/index.js
index 8c52ad1..740b96e 100644
--- a/index.js
+++ b/index.js
@@ -17,6 +17,8 @@ const interpret = tree => {
     return D.keepLow(interpret(tree.left), interpret(tree.right))
   case 'A':
     return D.again(interpret(tree.left), interpret(tree.right))
+  case 'a':
+    return D.againUnder(interpret(tree.left), interpret(tree.right))
   case 'T':
     return D.threshold(interpret(tree.left), interpret(tree.right))
   case 'add':