diff --git a/playbooks/tox/pre.yaml b/playbooks/tox/pre.yaml
index 2a3872f1..8e705439 100644
--- a/playbooks/tox/pre.yaml
+++ b/playbooks/tox/pre.yaml
@@ -1,5 +1,6 @@
 - hosts: all
   gather_facts: true
-  gather_subset: "!all"
+  gather_subset:
+    - "!all"
   roles:
     - run-bindep