input: Write a python function to fetch the last 200 tweets from a given Twitter handle using Tweepy and save them to a file named 'data.txt'.
  assert fetch_and_save_tweets('TwitterHandle') == None
output: import tweepy
  
  def fetch_and_save_tweets(handle):
      # Add your own credentials here
      consumer_key = 'your_consumer_key'
      consumer_secret = 'your_consumer_secret'
      access_token = 'your_access_token'
      access_token_secret = 'your_access_token_secret'
  
      # Authenticate to Twitter
      auth = tweepy.OAuth1UserHandler(consumer_key, consumer_secret, access_token, access_token_secret)
      api = tweepy.API(auth)
  
      # Fetch the last 200 tweets
      tweets = api.user_timeline(screen_name=handle, count=200, tweet_mode='extended')
  
      # Save tweets to 'data.txt'
      with open('data.txt', 'w', encoding='utf-8') as file:
          for tweet in tweets:
              file.write(tweet.full_text + '\n')