diff --git a/naive-nlu/tree_nlu/cli.py b/naive-nlu/tree_nlu/cli.py
index a4eee32..73a0a80 100644
--- a/naive-nlu/tree_nlu/cli.py
+++ b/naive-nlu/tree_nlu/cli.py
@@ -46,4 +46,8 @@ def main():
             else:
                 result.setter()
                 print("OK")
+        elif ret is None:
+            print("- Couldn't understand that, oops... -")
+        else:
+            print("Unhandled response:", ret)
     print("< Bye!")