diff --git a/pysd/py_backend/functions.py b/pysd/py_backend/functions.py
index 6464ce04..8c6930dd 100644
--- a/pysd/py_backend/functions.py
+++ b/pysd/py_backend/functions.py
@@ -840,7 +840,7 @@ def pulse_magnitude(magnitude, start, repeat_time=0):
     else:
         if abs((t - start) % repeat_time) < time_step:
             return magnitude * time_step
-        else
+        else:
             return 0