code: def sent_tokenize(text, tokenizer=None):
      
      _tokenizer = tokenizer if tokenizer is not None else NLTKPunktTokenizer()
      return SentenceTokenizer(tokenizer=_tokenizer).itokenize(text)
docs: Convenience function for tokenizing sentences (not iterable).
  
      If tokenizer is not specified, the default tokenizer NLTKPunktTokenizer()
      is used (same behaviour as in the main `TextBlob`_ library).
  
      This function returns the sentences as a generator object.
  
      .. _TextBlob: http://textblob.readthedocs.org/