From 69b6bf358693e44f20fd5f8f7d07fdabaa2cc647 Mon Sep 17 00:00:00 2001
From: zhurong <aaronzhu1121@gmail.com>
Date: Sat, 16 Feb 2019 10:32:00 +0800
Subject: [PATCH] Fix py37 unit test error

Closes-bug: #1789239
Change-Id: If252c58546a60630dff9427acb9a6ff2cc8244ca
(cherry picked from commit 9f4287ccc3f3ac467f56dc8bd12d3a35f03867c1)
---
 murano/dsl/helpers.py | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/murano/dsl/helpers.py b/murano/dsl/helpers.py
index 6d0911487..7f83260f2 100644
--- a/murano/dsl/helpers.py
+++ b/murano/dsl/helpers.py
@@ -737,10 +737,16 @@ def walk_gc(obj, towards, handler):
 
         visited.add(id(item))
         if towards:
-            queue.extend(
-                [(t, trace + [item]) for t in gc.get_referrers(item)]
-            )
+            try:
+                queue.extend(
+                    [(t, trace + [item]) for t in gc.get_referrers(item)]
+                )
+            except StopIteration:
+                return
         else:
-            queue.extend(
-                [(t, [item] + trace) for t in gc.get_referents(item)]
-            )
+            try:
+                queue.extend(
+                    [(t, [item] + trace) for t in gc.get_referents(item)]
+                )
+            except StopIteration:
+                return