input: 
  def identify_sentence_type(sentence: str) -> str:
      """ Identify whether a given sentence is an 'affirmative' sentence or a 'negative' sentence.
      >>> identify_sentence_type("He always comes late but I dont mind.")
      'Negative'
      >>> identify_sentence_type("She is always on time.")
      'Affirmative'
      """
  
output:     negative_words = ["not", "never", "no", "dont", "doesnt", "wont", "cant", "isnt", "arent"]
      words = sentence.lower().split()
      for word in words:
          if word in negative_words:
              return 'Negative'
      return 'Affirmative'