input: 
  def is_affirmative_or_negative(sentence: str) -> str:
      """Determine whether a given sentence is affirmative or negative.
      >>> is_affirmative_or_negative("He always comes late but I dont mind.")
      'Negative'
      >>> is_affirmative_or_negative("She loves to dance.")
      'Affirmative'
      """
      import re 
      import nltk
      nltk.download('stopwords')
      from nltk.corpus import stopwords 
  
      def find_negation(sentence):
          negationwords = {'not', 'never', 'no', 'none', 'non', 'neither',
                           'nobody', 'nowhere', 'cannot', 'couldnt', 'shouldnt', 
                           'wouldnt', 'dont', 'didnt', 'hasnt', 'havent', 'isnt', 'arent'} 
          words = nltk.word_tokenize(sentence)
          neg = []
          for word in words:
              if word in negationwords:
                  neg.append(word)
          return neg
  
      negationwords = find_negation(sentence)
      if len(negationwords) == 0: 
          return "Affirmative" 
      else: 
          return "Negative"
  
output:     import re 
      import nltk
      nltk.download('stopwords')
      from nltk.corpus import stopwords 
  
      def find_negation(sentence):
          negationwords = {'not', 'never', 'no', 'none', 'non', 'neither',
                           'nobody', 'nowhere', 'cannot', 'couldnt', 'shouldnt', 
                           'wouldnt', 'dont', 'didnt', 'hasnt', 'havent', 'isnt', 'arent'} 
          words = nltk.word_tokenize(sentence)
          neg = []
          for word in words:
              if word in negationwords:
                  neg.append(word)
          return neg
  
      negationwords = find_negation(sentence)
      if len(negationwords) == 0: 
          return "Affirmative" 
      else: 
          return "Negative"