code: def sentences(self, index = None):
          
          if index is None:
              return self.select(Sentence,None,True,[Quote])
          else:
              if index < 0:
                  index = sum(t.count(Sentence,None,True,[Quote]) for t in self.data) + index
              for t in self.data:
                  for i,e in enumerate(t.select(Sentence,None,True,[Quote])) :
                      if i == index:
                          return e
              raise IndexError
docs: Return a generator of all sentence found in the document. Except for sentences in quotes.
  
          If an index is specified, return the n'th sentence only (starting at 0)