diff --git a/undulator.py b/undulator.py
index 803857e..64cd0fc 100644
--- a/undulator.py
+++ b/undulator.py
@@ -68,7 +68,7 @@ class Undulators(Adjustable):
             
             if abs(delta)>0.001 :
                 print("E changed: waiting 10 sec for CHIC")
-                sleep(10
+                sleep(10)
             else :
                 sleep(2)
                 print("No E change: wainting 2 sec for CHIC")