From 8b39bbab45889d147a8d87e0037701ede44eeb09 Mon Sep 17 00:00:00 2001
From: Eddie Hebert <ehebert@quantopian.com>
Date: Fri, 4 Dec 2015 15:25:30 -0500
Subject: [PATCH] REF: Remove unused trading env member.

Usage of `prev_environment` was removed by a previous commit,
dc964a7e7da7e975b22fabfe962d2210704c1d6b
---
 zipline/finance/trading.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/zipline/finance/trading.py b/zipline/finance/trading.py
index 828ae7e9..9f64db97 100644
--- a/zipline/finance/trading.py
+++ b/zipline/finance/trading.py
@@ -96,7 +96,6 @@ class TradingEnvironment(object):
         self.open_and_closes = env_trading_calendar.open_and_closes.loc[
             self.trading_days]
 
-        self.prev_environment = self
         self.bm_symbol = bm_symbol
         if not load:
             load = load_market_data