From bed00a1b774c49a14026a600d02d41fce101966c Mon Sep 17 00:00:00 2001
From: Jean Bredeche <jean@quantopian.com>
Date: Mon, 24 Apr 2017 17:06:26 -0400
Subject: [PATCH] BUG: use isinstance

---
 zipline/finance/performance/period.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/zipline/finance/performance/period.py b/zipline/finance/performance/period.py
index 89ddbfd8..97664654 100644
--- a/zipline/finance/performance/period.py
+++ b/zipline/finance/performance/period.py
@@ -384,7 +384,7 @@ class PerformancePeriod(object):
         """
         Calculates the cash flow from executing the given transaction
         """
-        if txn.asset is Future:
+        if isinstance(txn.asset, Future):
             return 0.0
 
         return -1 * txn.price * txn.amount