diff --git a/src/Timers.py b/src/Timers.py
index d3a297df..7b595847 100644
--- a/src/Timers.py
+++ b/src/Timers.py
@@ -22,7 +22,7 @@ class Timer(object):
     def redo(self):
         self._done = False
         self.set_next_due()
-    def finish():
+    def finish(self):
         self._done = True
     def done(self):
         return self._done