Facing 401 Error while streaming tweets using python

The below image shows the code and error message .

I have pasted the code below

Code:

from tweepy import Stream
from tweepy import OAuthHandler
from tweepy.streaming import StreamListener


#consumer key, consumer secret, access token, access secret.
ckey=""
csecret=""
atoken=""
asecret=""

class listener(StreamListener):

    def on_data(self, data):
        print(data)
        return(True)

    def on_error(self, status):
        print status

auth = OAuthHandler(ckey, csecret)
auth.set_access_token(atoken, asecret)

twitterStream = Stream(auth, listener())
twitterStream.filter(track=["car","python"])

Sample Image: Please help me I am stuck with this for a long time.

Copyright Notice：Content Author:「Melvin Roy」，Reproduced under the CC 4.0 BY-SA copyright license with a link to the original source and this disclaimer.
Link to original article：https://stackoverflow.com/questions/39084694/facing-401-error-while-streaming-tweets-using-python