title: 401 Error when retrieving Twitter data using Tweepy
body: <p>I am trying to retrieve Twitter data using Tweepy, using that below code, but I'm returning 401 error, and I regenerate the access and secret tokens, and the same error appeared.</p>
  
  <pre><code>#imports
  from tweepy import Stream
  from tweepy import OAuthHandler
  from tweepy.streaming import StreamListener
  
  #setting up the keys
  consumer_key = 'xxxxxxx'
  consumer_secret = 'xxxxxxxx' 
  access_token = 'xxxxxxxxxx'
  access_secret = 'xxxxxxxxxxxxx'
  
  class TweetListener(StreamListener):
  # A listener handles tweets are the received from the stream.
  #This is a basic listener that just prints received tweets to standard output
  
     def on_data(self, data):
         print (data)
         return True
  
     def on_error(self, status):
         print (status)
  
  
  
  #printing all the tweets to the standard output
  auth = OAuthHandler(consumer_key, consumer_secret)
  auth.set_access_token(access_token, access_secret)
  
  
  
  stream = Stream(auth, TweetListener())
  
  t = u"#سوريا"
  stream.filter(track=[t])
  </code></pre>