diff --git a/docs/references/mqttclient.rst b/docs/references/mqttclient.rst
index 16d7e41..4b9a896 100644
--- a/docs/references/mqttclient.rst
+++ b/docs/references/mqttclient.rst
@@ -14,6 +14,12 @@ The example below shows how to write a simple MQTT client which subscribes a top
 
 .. code-block:: python
 
+    import logging
+    import asyncio
+
+    from hbmqtt.client import MQTTClient, ClientException
+    from hbmqtt.mqtt.constants import QOS_1, QOS_2
+
     @asyncio.coroutine
     def uptime_coro():
         C = MQTTClient()
@@ -53,6 +59,12 @@ This example also shows to method for publishing message asynchronously.
 
 .. code-block:: python
 
+    import logging
+    import asyncio
+
+    from hbmqtt.client import MQTTClient
+    from hbmqtt.mqtt.constants import QOS_1, QOS_2
+
     @asyncio.coroutine
     def test_coro():
         C = MQTTClient()
diff --git a/samples/client_publish_ssl.py b/samples/client_publish_ssl.py
index 47aea00..5b893e4 100644
--- a/samples/client_publish_ssl.py
+++ b/samples/client_publish_ssl.py
@@ -2,6 +2,7 @@ import logging
 import asyncio
 
 from hbmqtt.client import MQTTClient
+from hbmqtt.mqtt.constants import QOS_1, QOS_2
 
 
 
@@ -28,8 +29,8 @@ def test_coro():
     yield from C.connect('mqtts://test.mosquitto.org/', cafile='mosquitto.org.crt')
     tasks = [
         asyncio.ensure_future(C.publish('a/b', b'TEST MESSAGE WITH QOS_0')),
-        asyncio.ensure_future(C.publish('a/b', b'TEST MESSAGE WITH QOS_1', qos=0x01)),
-        asyncio.ensure_future(C.publish('a/b', b'TEST MESSAGE WITH QOS_2', qos=0x02)),
+        asyncio.ensure_future(C.publish('a/b', b'TEST MESSAGE WITH QOS_1', qos=QOS_1)),
+        asyncio.ensure_future(C.publish('a/b', b'TEST MESSAGE WITH QOS_2', qos=QOS_2)),
     ]
     yield from asyncio.wait(tasks)
     logger.info("messages published")
diff --git a/samples/client_publish_ws.py b/samples/client_publish_ws.py
index 03408f6..9bd239e 100644
--- a/samples/client_publish_ws.py
+++ b/samples/client_publish_ws.py
@@ -2,7 +2,7 @@ import logging
 import asyncio
 
 from hbmqtt.client import MQTTClient
-
+from hbmqtt.mqtt.constants import QOS_1, QOS_2
 
 
 #
@@ -29,8 +29,8 @@ def test_coro():
     yield from C.connect('wss://test.mosquitto.org:8081/', cafile='mosquitto.org.crt')
     tasks = [
         asyncio.ensure_future(C.publish('a/b', b'TEST MESSAGE WITH QOS_0')),
-        asyncio.ensure_future(C.publish('a/b', b'TEST MESSAGE WITH QOS_1', qos=0x01)),
-        asyncio.ensure_future(C.publish('a/b', b'TEST MESSAGE WITH QOS_2', qos=0x02)),
+        asyncio.ensure_future(C.publish('a/b', b'TEST MESSAGE WITH QOS_1', qos=QOS_1)),
+        asyncio.ensure_future(C.publish('a/b', b'TEST MESSAGE WITH QOS_2', qos=QOS_2)),
     ]
     yield from asyncio.wait(tasks)
     logger.info("messages published")