new_contents: """corpus."""
  
  
  from abc import ABCMeta
  
  from six import with_metaclass, u
  
  
  class Corpus(with_metaclass(ABCMeta)):
      """Abstract class for corpus."""
  
      def iter_tokenized_sentences(self, lower=True, stem=False):
          """Yield string with tokenized sentences.
  
          Parameters
          ----------
          lower : bool, default True
              Lower case the words.
          stem : bool, default False
              Apply word stemming. DanishStemmer from nltk is used.
  
          Yields
          ------
          tokenized_sentence : str
              Sentence as string with tokens separated by a whitespace.
  
          """
          for words in self.iter_sentence_words(lower=lower, stem=stem):
              tokenized_sentence = u(" ").join(words)
              yield tokenized_sentence
  
subject: Create corpus.py