Subclasses may override this method.

def _get_bcpIn(self):
        """
        Subclasses may override this method.
        """
        segment = self._segment
        offCurves = segment.offCurve
        if offCurves:
            bcp = offCurves[-1]
            x, y = relativeBCPIn(self.anchor, (bcp.x, bcp.y))
        else:
            x = y = 0
        return (x, y)