diff --git a/moto/ec2/models.py b/moto/ec2/models.py
index 73b16be3d..5b1f5a1d6 100644
--- a/moto/ec2/models.py
+++ b/moto/ec2/models.py
@@ -377,7 +377,7 @@ class SecurityGroupBackend(object):
         # 2 levels of chaining necessary since it's a complex structure
         all_groups = itertools.chain.from_iterable([x.values() for x in self.groups.values()])
 
-        for group in itertools.chain(all_groups):
+        for group in all_groups:
             if group.id == group_id:
                 return group
 
@@ -452,7 +452,7 @@ class SecurityGroupBackend(object):
             source_group = self.get_security_group_from_id(source_group_id)
             if source_group:
                 source_groups.append(source_group)
-                
+
         security_rule = SecurityRule(ip_protocol, from_port, to_port, ip_ranges, source_groups)
         if security_rule in group.ingress_rules:
             group.ingress_rules.remove(security_rule)
diff --git a/tests/test_ec2/test_security_groups.py b/tests/test_ec2/test_security_groups.py
index fe330e17f..27d523e41 100644
--- a/tests/test_ec2/test_security_groups.py
+++ b/tests/test_ec2/test_security_groups.py
@@ -142,6 +142,8 @@ def test_authorize_group_in_vpc():
     security_group2 = conn.create_security_group('test2', 'test2', vpc_id)
 
     success = security_group1.authorize(ip_protocol="tcp", from_port="22", to_port="2222", src_group=security_group2)
+    success.should.be.true
     success = security_group1.revoke(ip_protocol="tcp", from_port="22", to_port="2222", src_group=security_group2)
+    success.should.be.true