except BaseException as e: keeps throwing an error – Twitter API

I’m following a tutorial about analyzing twitter data. I’m wondering why I keep getting a syntax error on line 44: except BaseException as e:

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

import twitter_credentials
#TWITTER AUTHENTICATOR
class TwitterAuthenticator():

    def authenticate_twitter_app(self):
        auth = OAuthHandler(twitter_credentials.CONSUMER_KEY, twitter_credentials.CONSUMER_SECRET)
        auth.set_access_token(twitter_credentials.ACCESS_TOKEN, twitter_credentials.ACCESS_TOKEN_SECRET)
        return auth

#TWITTER STREAMER
class TwitterStreamer():

#Class for streaming and processing live tweets
    def __init__(self):
        self.twitter_authenticator = TwitterAuthenticator()


    def stream_tweets(self, fetched_tweets_filename, hash_tag_list):
        #This handles Twitter authentication and connection to the Twitter streaming API
        listener = TwitterListener()
        auth = self.twitter_authenticator.authenticate_twitter_app()
        stream = Stream(auth, listener)

        stream.filter(track=hash_tag_list)

class TwitterListener(StreamListener):
#Basic listener class that just prints received tweets to stdout
    def __init__(self, fetched_tweets_filename):
        self.fetched_tweets_filename = fetched_tweets_filename


    def on_data(self, data):
        try:
            print(data)
            with open(self.fetched_tweets_filename, 'a') as tf:
                tf.write(data)
                return True
            except BaseException as e:
                    print('Error on_data %s' % str(e))
                return True

    def on_error(self, status):
        print(status)


if __name__ == '__main__':

    hash_tag_list['kevin durant', 'steph curry', 'clippers']
    fetched_tweets_filename = 'tweets.json'

    twitter_streamer = TwitterStreamer()
    twitter_streamer.stream_tweets(fetched_tweets_filename, hash_tag_list)