From 0848ef9f9b3c48665b744cb28cf3a2f417020019 Mon Sep 17 00:00:00 2001
From: fawce <fawce@quantopian.com>
Date: Tue, 7 Aug 2012 20:17:41 -0400
Subject: [PATCH] tweaks to patch leaky abstractions

---
 zipline/gens/merge.py   | 4 ++++
 zipline/gens/returns.py | 2 +-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/zipline/gens/merge.py b/zipline/gens/merge.py
index c4afb1b4..0689d507 100644
--- a/zipline/gens/merge.py
+++ b/zipline/gens/merge.py
@@ -66,6 +66,10 @@ def merge_one(sources):
 
         # Merge any remaining fields into the event dict.
         event_fields.merge(message)
+
+    # alias dt with datetime, per algoscript api
+    event_fields['datetime'] = event_fields['dt']
+
     return event_fields
 
 
diff --git a/zipline/gens/returns.py b/zipline/gens/returns.py
index 055b9735..ccfc7b00 100644
--- a/zipline/gens/returns.py
+++ b/zipline/gens/returns.py
@@ -34,7 +34,7 @@ class ReturnsFromPriorClose(object):
     def __init__(self, days):
         self.closes = deque()
         self.last_event = None
-        self.returns = None
+        self.returns = 0.0
         self.days = days
 
     def get_returns(self):