docs: def split(self, point=None):
      """
        Split this sequence into two halves and return them. The original
        sequence remains unmodified.
  
        :param point: defines the split point, if None then the centre is used
        :return: two Sequence objects -- one for each side
      """
      if point is None:
        point = len(self) / 2
  
      r1 = Sequence(self.name + ".1", self.sequenceData[:point])
      r2 = Sequence(self.name + ".2", self.sequenceData[point:])
  
      return r1, r2