diff --git a/docker/examples/simple/my.config.yml b/docker/examples/simple/my.config.yml
index 569f7ef..a94be46 100644
--- a/docker/examples/simple/my.config.yml
+++ b/docker/examples/simple/my.config.yml
@@ -158,7 +158,7 @@ datasets:
             spatial:
                 bbox: [-180,-90,180,90]
             temporal:
-                begin: None
+                begin:
                 end: now  # or empty
         provider: 
             name: SQLite