input: Write a function to remove all punctuation from a string and capitalize the first letter of each word.
  assert clean_string("hello, world!") == "Hello World"
  assert clean_string("this is a test.") == "This Is A Test"
  assert clean_string("python is great! isn't it?") == "Python Is Great Isnt It"
output: import string
  
  def clean_string(s):
      translator = str.maketrans('', '', string.punctuation)
      no_punctuation = s.translate(translator)
      return no_punctuation.title()