input: Write a function that can classify a given sentence as either 'affirmative' or 'negative' based on the presence of negation words. The function should utilize Natural Language Processing techniques to accurately identify negation words in the sentence and then determine the sentence type.
  
  assert isAffirmativeorNegative("He always comes late but I don't mind.") == "Negative"
  assert isAffirmativeorNegative("She is always on time.") == "Affirmative"
  assert isAffirmativeorNegative("Nobody was happy about the outcome.") == "Negative"
  assert isAffirmativeorNegative("The weather is great today.") == "Affirmative"
output: def isAffirmativeorNegative(sentence):
      negation_words = ["not", "no", "never", "none", "nobody", "nothing", "neither", "nowhere", "hardly", "scarcely", "barely", "don't", "doesn't", "isn't", "aren't", "wasn't", "weren't", "hasn't", "haven't", "hadn't", "won't", "wouldn't", "shouldn't", "can't", "cannot", "couldn't", "mustn't"]
      words = sentence.lower().split()
      for word in words:
          if word in negation_words:
              return "Negative"
      return "Affirmative"