input: Write a python function to preprocess the tweets by lowercasing the text and removing punctuation.
  assert preprocess_tweets("Hello World!") == "hello world "
  assert preprocess_tweets("Python, Java & C++") == "python  java   c "
  assert preprocess_tweets("Happy Coding!!!") == "happy coding "
output: def preprocess_tweets(tweet):
      import string
      tweet = tweet.lower()
      tweet = tweet.translate(str.maketrans(string.punctuation, ' ' * len(string.punctuation)))
      return tweet