code: def _insertSegment(self, index=None, type=None, points=None,
                         smooth=False, **kwargs):
          
          onCurve = points[-1]
          offCurve = points[:-1]
          segments = self.segments
          ptCount = sum([len(segments[s].points) for s in range(index)]) + 1
          self.insertPoint(ptCount, onCurve, type=type, smooth=smooth)
          for offCurvePoint in reversed(offCurve):
              self.insertPoint(ptCount, offCurvePoint, type="offcurve")
docs: Subclasses may override this method.