input: Write a function to visually summarize the Twitter data. The function should take a stream of tweets as input, where each tweet has data fields like tweet author, date of tweet, text, number of likes, and number of retweets. The function should use matplotlib to plot visual summaries for tweet authors, number of likes, and number of retweets.
  assert summarize_twitter_data([{'author': 'A', 'date': '2023-01-01', 'text': 'Hello', 'likes': 10, 'retweets': 5}, {'author': 'B', 'date': '2023-01-02', 'text': 'Hi', 'likes': 15, 'retweets': 7}])==None
  assert summarize_twitter_data([])==None
output: def summarize_twitter_data(tweets):
      if not tweets:
          return None
      
      authors = [tweet['author'] for tweet in tweets]
      likes = [tweet['likes'] for tweet in tweets]
      retweets = [tweet['retweets'] for tweet in tweets]
      
      fig, ax = plt.subplots(3, 1, figsize=(10, 15))
      
      ax[0].bar(authors, likes)
      ax[0].set_title('Number of Likes per Author')
      ax[0].set_xlabel('Author')
      ax[0].set_ylabel('Likes')
      
      ax[1].bar(authors, retweets)
      ax[1].set_title('Number of Retweets per Author')
      ax[1].set_xlabel('Author')
      ax[1].set_ylabel('Retweets')
      
      ax[2].scatter(likes, retweets)
      ax[2].set_title('Likes vs Retweets')
      ax[2].set_xlabel('Likes')
      ax[2].set_ylabel('Retweets')
      
      plt.tight_layout()
      plt.show()
      
      return None