input: Write a function to visually summarize the Twitter data using matplotlib. The function should process the Twitter data to extract relevant fields such as tweet authors, date of tweet, text, number of likes, and number of retweets, and then generate bar plots summarizing the data. The function should return None.
  
  assert visually_summarize_twitter_data(twitter_data) == None
  
  twitter_data = [
      {"author": "User1", "date": "2023-10-01", "text": "Hello world", "likes": 10, "retweets": 5},
      {"author": "User2", "date": "2023-10-02", "text": "Python is awesome", "likes": 20, "retweets": 10},
      {"author": "User1", "date": "2023-10-03", "text": "AI is the future", "likes": 15, "retweets": 8},
  ]
  
  assert visually_summarize_twitter_data(twitter_data) == None
output: def visually_summarize_twitter_data(twitter_data):
      authors = [tweet['author'] for tweet in twitter_data]
      likes = [tweet['likes'] for tweet in twitter_data]
      retweets = [tweet['retweets'] for tweet in twitter_data]
      
      fig, ax = plt.subplots(2, 1, figsize=(10, 8))
      
      ax[0].bar(authors, likes, color='skyblue')
      ax[0].set_title('Number of Likes per Author')
      ax[0].set_xlabel('Author')
      ax[0].set_ylabel('Likes')
      
      ax[1].bar(authors, retweets, color='salmon')
      ax[1].set_title('Number of Retweets per Author')
      ax[1].set_xlabel('Author')
      ax[1].set_ylabel('Retweets')
      
      plt.tight_layout()
      plt.show()
      
      return None