From 2a750fa6964ffebecd7804953db3b413a1a83bc3 Mon Sep 17 00:00:00 2001
From: Lonami Exo <totufals@hotmail.com>
Date: Wed, 2 Mar 2022 13:01:28 +0100
Subject: [PATCH] Ignore ChannelParticipantLeft

Closes #3252.
---
 telethon/_client/chats.py | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/telethon/_client/chats.py b/telethon/_client/chats.py
index f132d66d..8737e576 100644
--- a/telethon/_client/chats.py
+++ b/telethon/_client/chats.py
@@ -205,6 +205,10 @@ class _ParticipantsIter(requestiter.RequestIter):
             else:
                 user_id = participant.user_id
 
+            if isinstance(participant, types.ChannelParticipantLeft):
+                # These participants should be ignored. See #3231.
+                continue
+
             user = users[user_id]
             if not self.filter_entity(user) or user.id in self.seen:
                 continue