diff --git a/zipline/gens/tradegens.py b/zipline/gens/tradegens.py
index c7ee74f8..1d9021d7 100644
--- a/zipline/gens/tradegens.py
+++ b/zipline/gens/tradegens.py
@@ -9,9 +9,9 @@ from datetime import datetime, timedelta
 from zipline.utils.factory import create_trade
 from zipline.gens.utils import hash_args, mock_done
 
-def date_gen(start = datetime(2012, 6, 6, 0),
-             delta = timedelta(minutes = 1),
-             count = 100):
+def date_gen(start=datetime(2012, 6, 6, 0),
+             delta=timedelta(minutes = 1),
+             count=100):
     """
     Utility to generate a stream of dates.
     """