code: def tokenize_text(string):
      
      string = six.text_type(string)
      rez = []
      for part in string.split('\n'):
          par = []
          for sent in tokenize_sents(part):
              par.append(tokenize_words(sent))
          if par:
              rez.append(par)
      return rez
docs: Tokenize input text to paragraphs, sentences and words.
  
      Tokenization to paragraphs is done using simple Newline algorithm
      For sentences and words tokenizers above are used
  
      :param string: Text to tokenize
      :type string: str or unicode
      :return: text, tokenized into paragraphs, sentences and words
      :rtype: list of list of list of words