input: Write a function to identify whether a given sentence is an 'affirmative' sentence or a 'negative' sentence. The function should tokenize the sentence and check for negation words. If the sentence contains any negation words, it should be classified as 'Negative', otherwise 'Affirmative'.
  assert isAffirmativeorNegative("He always comes late but I dont mind.") == "Negative"
  assert isAffirmativeorNegative("She is always on time.") == "Affirmative"
  assert isAffirmativeorNegative("I am feeling happy today.") == "Affirmative"
  assert isAffirmativeorNegative("I never go to the park.") == "Negative"
  assert isAffirmativeorNegative("There is no problem.") == "Negative"
output: def isAffirmativeorNegative(sentence):
      negation_words = {"not", "never", "no", "dont", "isnt", "arent", "cant", "wont", "doesnt", "didnt", "hasnt", "havent", "hadnt", "shouldnt", "wouldnt", "couldnt", "werent", "aint"}
      tokens = sentence.lower().split()
      for word in tokens:
          if word in negation_words:
              return "Negative"
      return "Affirmative"