From d0c566bbdb923898b91a1f629384fc8511a45540 Mon Sep 17 00:00:00 2001
From: Nikolay Tretyak <ndtretyak@users.noreply.github.com>
Date: Sat, 4 Aug 2018 12:30:24 +0300
Subject: [PATCH] Fix iter_participants is failing when _total is None (#936)

---
 telethon/client/chats.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/telethon/client/chats.py b/telethon/client/chats.py
index 5a5550f0..3680f7c2 100644
--- a/telethon/client/chats.py
+++ b/telethon/client/chats.py
@@ -137,7 +137,8 @@ class ChatMethods(UserMethods):
             if not isinstance(
                     full.full_chat.participants, types.ChatParticipants):
                 # ChatParticipantsForbidden won't have ``.participants``
-                _total[0] = 0
+                if _total:
+                    _total[0] = 0
                 return
 
             if _total: