---
 dolfin_adjoint/timeforms.py |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/dolfin_adjoint/timeforms.py
+++ b/dolfin_adjoint/timeforms.py
@@ -211,7 +211,7 @@ class TimeMeasure(object):
             interval = slice(START_TIME,FINISH_TIME,None)
 
         if interval not in (START_TIME,FINISH_TIME) and not isinstance(interval, (slice, int, float)):
-            raise ValueError, "TimeMeasure can only be indexed with floats, START_TIME and FINISH_TIME."
+            raise(ValueError, "TimeMeasure can only be indexed with floats, START_TIME and FINISH_TIME.")
 
         self.interval = timeslice(interval)