From d686fac02d9dee15aad13f6ff7e20d02f6c7227b Mon Sep 17 00:00:00 2001
From: Eddie Hebert <ehebert@quantopian.com>
Date: Sun, 5 May 2013 04:43:10 -0400
Subject: [PATCH] MAINT: Use property for tradesimulation perf_key.

---
 zipline/gens/tradesimulation.py | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/zipline/gens/tradesimulation.py b/zipline/gens/tradesimulation.py
index 69078570..dd409f05 100644
--- a/zipline/gens/tradesimulation.py
+++ b/zipline/gens/tradesimulation.py
@@ -54,9 +54,6 @@ class AlgorithmSimulator(object):
                                                   second=0,
                                                   microsecond=0)
 
-        self.perf_key = self.EMISSION_TO_PERF_KEY_MAP[
-            self.algo.perf_tracker.emission_rate]
-
         # ==============
         # Snapshot Setup
         # ==============
@@ -82,6 +79,11 @@ class AlgorithmSimulator(object):
                 record.extra['algo_dt'] = self.snapshot_dt
         self.processor = Processor(inject_algo_dt)
 
+    @property
+    def perf_key(self):
+        return self.EMISSION_TO_PERF_KEY_MAP[
+            self.algo.perf_tracker.emission_rate]
+
     def transform(self, stream_in):
         """
         Main generator work loop.