input: Write a function to determine if a given sentence is an 'affirmative' sentence or a 'negative' sentence by identifying negation words. If no negation words are found, the sentence is considered 'affirmative'; otherwise, it is considered 'negative'. If the input sentence is empty, it should also be considered 'affirmative'.
  
  assert isAffirmativeorNegative("He always comes on time. I am glad.") == "Affirmative"
  assert isAffirmativeorNegative("He always comes late but I don't mind.") == "Negative"
  assert isAffirmativeorNegative("No one can complete this task.") == "Negative"
  assert isAffirmativeorNegative("") == "Affirmative"
  assert isAffirmativeorNegative("I cannot believe this.") == "Negative"
output: def isAffirmativeorNegative(sentence):
      negation_words = ["no", "not", "never", "none", "nobody", "nothing", "neither", "nowhere", "hardly", "scarcely", "barely", "don't", "doesn't", "didn't", "isn't", "aren't", "wasn't", "weren't", "can't", "couldn't", "shouldn't", "wouldn't", "won't", "shan't"]
      if not sentence:
          return "Affirmative"
      for word in negation_words:
          if word in sentence.lower():
              return "Negative"
      return "Affirmative"