input: def summarize_twitter_data(twitter_data: List[Dict[str, Union[str, int]]]) -> None:
      """ Summarize the Twitter data by plotting the number of tweets per author, 
      the number of likes per tweet, and the number of retweets per tweet.
      
      >>> summarize_twitter_data([
      ... {'author': 'User1', 'date': '2023-01-01', 'text': 'Hello World', 'likes': 10, 'retweets': 2},
      ... {'author': 'User2', 'date': '2023-01-02', 'text': 'Nice day', 'likes': 5, 'retweets': 1},
      ... {'author': 'User1', 'date': '2023-01-03', 'text': 'Another tweet', 'likes': 8, 'retweets': 3}
      ... ])
      """
output:     import matplotlib.pyplot as plt
      from collections import defaultdict
  
      authors = defaultdict(int)
      likes = []
      retweets = []
  
      for tweet in twitter_data:
          authors[tweet['author']] += 1
          likes.append(tweet['likes'])
          retweets.append(tweet['retweets'])
  
      plt.figure(figsize=(12, 4))
  
      plt.subplot(1, 3, 1)
      plt.bar(authors.keys(), authors.values())
      plt.xlabel('Authors')
      plt.ylabel('Number of Tweets')
      plt.title('Tweets per Author')
  
      plt.subplot(1, 3, 2)
      plt.hist(likes, bins=10, edgecolor='black')
      plt.xlabel('Number of Likes')
      plt.ylabel('Frequency')
      plt.title('Likes per Tweet')
  
      plt.subplot(1, 3, 3)
      plt.hist(retweets, bins=10, edgecolor='black')
      plt.xlabel('Number of Retweets')
      plt.ylabel('Frequency')
      plt.title('Retweets per Tweet')
  
      plt.tight_layout()
      plt.show()