code: def split(self, sep=TOKENS):
          
          if sep != TOKENS:
              return unicode.split(self, sep)
          if len(self) == 0:
              return []
          return [[[x.replace("&slash;", "/") for x in token.split("/")]
              for token in sentence.split(" ")]
                  for sentence in unicode.split(self, "\n")]
docs: Returns a list of sentences, where each sentence is a list of tokens,
              where each token is a list of word + tags.