input: Below is an instruction that describes a task. Write a response that appropriately completes the request.
  
  ### Instruction:
  Write a Python program to visually summarize the Twitter data.
  
  ### Input:
  Twitter data is a stream of tweets with data fields like : tweet author, date of tweet, text, number of likes, number of retweets.
  
  ### Output:
  import matplotlib.pyplot as plt
  
  # Process the Twitter data to extract
  # the relevant data fields
  # ...
  
  # Plot the tweet authors
  plt.xlabel('Tweet Authors')
  plt.ylabel('Number of tweets')
  plt.title('Tweet Author Summary')
  plt.bar(authors, num_tweets)
  plt.show()
  
  # Plot the number of likes
  plt.xlabel('Tweets')
  plt.ylabel('Number of Likes')
  plt.title('Number of Likes Summary')
  plt.bar(tweets, num_likes)
  plt.show()
  
  # Plot the number of retweets
  plt.xlabel('Tweets')
  plt.ylabel('Number of Retweets')
  plt.title('Number of Retweets Summary')
  plt.bar(tweets, num_retweets)
  plt.show()
output:     
  import matplotlib.pyplot as plt
  
  # Process the Twitter data to extract
  # the relevant data fields
  authors = [tweet['author'] for tweet in twitter_data]
  num_tweets = [authors.count(author) for author in set(authors)]
  tweets = [tweet['text'] for tweet in twitter_data]
  num_likes = [tweet['likes'] for tweet in twitter_data]
  num_retweets = [tweet['retweets'] for tweet in twitter_data]
  
  # Plot the tweet authors
  plt.xlabel('Tweet Authors')
  plt.ylabel('Number of tweets')
  plt.title('Tweet Author Summary')
  plt.bar(set(authors), num_tweets)
  plt.show()
  
  # Plot the number of likes
  plt.xlabel('Tweets')
  plt.ylabel('Number of Likes')
  plt.title('Number of Likes Summary')
  plt.bar(range(len(tweets)), num_likes)
  plt.show()
  
  # Plot the number of retweets
  plt.xlabel('Tweets')
  plt.ylabel('Number of Retweets')
  plt.title('Number of Retweets Summary')
  plt.bar(range(len(tweets)), num_retweets)
  plt.show()
  