code: def slice(self, start, until):
          
          return self._transform(transformations.slice_t(start, until))
docs: Takes a slice of the sequence starting at start and until but not including until.
  
          >>> seq([1, 2, 3, 4]).slice(1, 2)
          [2]
          >>> seq([1, 2, 3, 4]).slice(1, 3)
          [2, 3]
  
          :param start: starting index
          :param until: ending index
          :return: slice including start until but not including until