diff --git a/hbmqtt/client.py b/hbmqtt/client.py
index 253a5a0..e0b98b3 100644
--- a/hbmqtt/client.py
+++ b/hbmqtt/client.py
@@ -430,7 +430,7 @@ class MQTTClient:
     @asyncio.coroutine
     def handle_connection_close(self):
 
-        def cancel_tasks(self):
+        def cancel_tasks():
             while self.client_tasks:
                 task = self.client_tasks.popleft()
                 if not task.done():
@@ -456,7 +456,7 @@ class MQTTClient:
                 yield from self.reconnect()
             except ConnectException:
                 # Cancel client pending tasks
-                cancel_tasks(self)
+                cancel_tasks()
         else:
             # Cancel client pending tasks
             cancel_tasks()
diff --git a/hbmqtt/mqtt/puback.py b/hbmqtt/mqtt/puback.py
index 7bbd065..12e72cd 100644
--- a/hbmqtt/mqtt/puback.py
+++ b/hbmqtt/mqtt/puback.py
@@ -6,7 +6,6 @@ from hbmqtt.errors import HBMQTTException
 
 
 class PubackPacket(MQTTPacket):
-
     VARIABLE_HEADER = PacketIdVariableHeader
     PAYLOAD = None