diff --git a/backend/stream.py b/backend/stream.py
index ab2b4bd..baf2feb 100755
--- a/backend/stream.py
+++ b/backend/stream.py
@@ -67,9 +67,9 @@ class ProxyElem():
             logger.info(e)
         if isinstance(jdata, list):
             ret_data = []
-            for i in range(len(jdata)):
-                if isinstance(urls[i], str):
-                    ret_data.append(jdata[i])
+            for src, dst in zip(urls, jdata):
+                if isinstance(src, str):
+                    ret_data.append(dst)
                 else:
                     ret_data.append(None)
             return ret_data