input: 
  import matplotlib.pyplot as plt
  from typing import List, Dict
  
  def summarize_twitter_data(tweets: List[Dict[str, str]]) -> None:
      """Given a list of tweets with fields like 'author', 'date', 'text', 'likes', and 'retweets',
      this function processes the data and generates visual summaries for tweet authors,
      the number of likes per tweet, and the number of retweets per tweet.
      >>> tweets = [
      ...     {'author': 'User1', 'date': '2023-01-01', 'text': 'Tweet1', 'likes': '10', 'retweets': '5'},
      ...     {'author': 'User2', 'date': '2023-01-02', 'text': 'Tweet2', 'likes': '5', 'retweets': '2'},
      ...     {'author': 'User1', 'date': '2023-01-03', 'text': 'Tweet3', 'likes': '15', 'retweets': '7'}
      ... ]
      >>> summarize_twitter_data(tweets)
      # Three charts displayed:
      # 1) Tweet Authors vs Number of Tweets
      # 2) Tweets vs Number of Likes
      # 3) Tweets vs Number of Retweets
      """
      authors = {}
      likes = {}
      retweets = {}
      
      for tweet in tweets:
          author = tweet['author']
          like_count = int(tweet['likes'])
          retweet_count = int(tweet['retweets'])
          
          if author in authors:
              authors[author] += 1
          else:
              authors[author] = 1
          
          likes[tweet['text']] = like_count
          retweets[tweet['text']] = retweet_count
      
      author_names = list(authors.keys())
      num_tweets = list(authors.values())
      tweet_texts = list(likes.keys())
      num_likes = list(likes.values())
      num_retweets = list(retweets.values())
      
      plt.xlabel('Tweet Authors')
      plt.ylabel('Number of Tweets')
      plt.title('Tweet Author Summary')
      plt.bar(author_names, num_tweets)
      plt.show()
      
      plt.xlabel('Tweets')
      plt.ylabel('Number of Likes')
      plt.title('Number of Likes Summary')
      plt.bar(tweet_texts, num_likes)
      plt.show()
      
      plt.xlabel('Tweets')
      plt.ylabel('Number of Retweets')
      plt.title('Number of Retweets Summary')
      plt.bar(tweet_texts, num_retweets)
      plt.show()
  
output:     plt.xlabel('Tweet Authors')
      plt.ylabel('Number of Tweets')
      plt.title('Tweet Author Summary')
      plt.bar(author_names, num_tweets)
      plt.show()
      
      plt.xlabel('Tweets')
      plt.ylabel('Number of Likes')
      plt.title('Number of Likes Summary')
      plt.bar(tweet_texts, num_likes)
      plt.show()
      
      plt.xlabel('Tweets')
      plt.ylabel('Number of Retweets')
      plt.title('Number of Retweets Summary')
      plt.bar(tweet_texts, num_retweets)
      plt.show()