From f62ce30dbf3099b5b74a03574a7e71dbc5efc971 Mon Sep 17 00:00:00 2001
From: Dan <14043624+delivrance@users.noreply.github.com>
Date: Tue, 26 Dec 2017 01:19:38 +0100
Subject: [PATCH] Check if not None before calling .join()

---
 pyrogram/session/session.py | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/pyrogram/session/session.py b/pyrogram/session/session.py
index d27c6a83..b68e3fa0 100644
--- a/pyrogram/session/session.py
+++ b/pyrogram/session/session.py
@@ -164,8 +164,11 @@ class Session:
         self.ping_thread_event.set()
         self.next_salt_thread_event.set()
 
-        self.ping_thread.join()
-        self.next_salt_thread.join()
+        if self.ping_thread is not None:
+            self.ping_thread.join()
+
+        if self.next_salt_thread is not None:
+            self.next_salt_thread.join()
 
         self.ping_thread_event.clear()
         self.next_salt_thread_event.clear()