input: Write a function to determine whether a given sentence is an 'affirmative' sentence or a 'negative' sentence. If the sentence is affirmative, return "Affirmative". If the sentence is negative, return "Negative".
  assert isAffirmativeorNegative("He always comes late but I dont mind.") == "Negative"
  assert isAffirmativeorNegative("She is always on time.") == "Affirmative"
  assert isAffirmativeorNegative("I have never seen a prettier sunset.") == "Negative"
  assert isAffirmativeorNegative("No one could have done it better.") == "Negative"
  assert isAffirmativeorNegative("Everyone enjoyed the concert.") == "Affirmative"
output: def isAffirmativeorNegative(sentence):
      negative_words = ["not", "never", "no", "dont", "couldnt", "wouldnt", "shouldnt", "wont", "cant", "doesnt", "isnt", "arent"]
      words = sentence.lower().split()
      for word in words:
          if word in negative_words:
              return "Negative"
      return "Affirmative"