modified do not order guard to take an iteratble or a container

container allows for dynamic restrictions, necessary for a
point in time implementation of the restricted list.

tests/test_algorithm.py

@@ -958,17 +958,19 @@ class TestTradingControls(TestCase):
 
     def test_set_do_not_order_list(self):
         # set the restricted list to be the sid, and fail.
-        algo = SetDoNotOrderListAlgorithm(sid=self.sid,
+        algo = SetDoNotOrderListAlgorithm(
+            sid=self.sid,
             restricted_list=[self.sid])
 
         def handle_data(algo, data):
             algo.order(self.sid, 100)
             algo.order_count += 1
-            
+
         self.check_algo_fails(algo, handle_data, 0)
 
         # set the restricted list to exclude the sid, and succeed
-        algo = SetDoNotOrderListAlgorithm(sid=self.sid,
+        algo = SetDoNotOrderListAlgorithm(
+            sid=self.sid,
             restricted_list=[134, 135, 136])
 
         def handle_data(algo, data):

zipline/finance/controls.py

@@ -106,9 +106,14 @@ class RestrictedListOrder(TradingControl):
     """
 
     def __init__(self, restricted_list):
+        """
+        restricted list can be an iterable, or
+        an object that implements __contains__ for dynamic
+        restrictions.
+        """
 
         super(RestrictedListOrder, self).__init__()
-        self.restricted_list = set(restricted_list)
+        self.restricted_list = restricted_list
 
     def validate(self,
                  sid,