input: import matplotlib.pyplot as plt
  
  def visualize_twitter_data(tweets):
      """Visually summarize the Twitter data by plotting the number of tweets per author,
      number of likes per tweet, and number of retweets per tweet.
      
      Example:
      >>> visualize_twitter_data([{'author': 'User1', 'date': '2023-01-01', 'text': 'Hello', 'likes': 10, 'retweets': 5}, 
      ...                        {'author': 'User2', 'date': '2023-01-02', 'text': 'World', 'likes': 5, 'retweets': 2}, 
      ...                        {'author': 'User1', 'date': '2023-01-03', 'text': 'Hi', 'likes': 8, 'retweets': 3}])
      # This will generate three bar plots: one for tweet authors, one for likes, and one for retweets.
      """
output:     authors = [tweet['author'] for tweet in tweets]
      likes = [tweet['likes'] for tweet in tweets]
      retweets = [tweet['retweets'] for tweet in tweets]
  
      author_counts = {author: authors.count(author) for author in set(authors)}
  
      fig, axs = plt.subplots(3, 1, figsize=(10, 15))
  
      axs[0].bar(author_counts.keys(), author_counts.values())
      axs[0].set_title('Number of Tweets per Author')
      axs[0].set_xlabel('Author')
      axs[0].set_ylabel('Number of Tweets')
  
      axs[1].bar(range(len(likes)), likes)
      axs[1].set_title('Number of Likes per Tweet')
      axs[1].set_xlabel('Tweet Index')
      axs[1].set_ylabel('Number of Likes')
  
      axs[2].bar(range(len(retweets)), retweets)
      axs[2].set_title('Number of Retweets per Tweet')
      axs[2].set_xlabel('Tweet Index')
      axs[2].set_ylabel('Number of Retweets')
  
      plt.tight_layout()
      plt.show()