From dc14f0e9ff793f8137eb19a1da046b2ed45ace54 Mon Sep 17 00:00:00 2001
From: Eddie Hebert <ehebert@quantopian.com>
Date: Wed, 12 Jun 2013 13:26:31 -0400
Subject: [PATCH] MAINT: Remove _period_trading_days member from
 TradingEnvironment.

Now that the period_trading_days method is removed, the internal
member that cached the value, is also no longer needed.
---
 zipline/finance/trading.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/zipline/finance/trading.py b/zipline/finance/trading.py
index 331373f0..08164538 100644
--- a/zipline/finance/trading.py
+++ b/zipline/finance/trading.py
@@ -92,7 +92,6 @@ class TradingEnvironment(object):
         if max_date:
             self.treasury_curves = self.treasury_curves[:max_date]
 
-        self._period_trading_days = None
         self._trading_days_series = None
         self.full_trading_day = datetime.timedelta(hours=6, minutes=30)
         self.exchange_tz = exchange_tz