code: def find_lemmata(tokens):
      
      for token in tokens:
          word, pos, lemma = token[0], token[1], token[0]
          if pos.startswith(("DT", "JJ")):
              lemma = predicative(word)  
          if pos == "NNS":
              lemma = singularize(word)
          if pos.startswith(("VB", "MD")):
              lemma = conjugate(word, INFINITIVE) or word
          token.append(lemma.lower())
      return tokens
docs: Annotates the tokens with lemmata for plural nouns and conjugated verbs,
          where each token is a [word, part-of-speech] list.