def save(self):
        tmp_path = self.path + '.tmp'
        with open(tmp_path, 'w') as f:
            f.write(json.dumps(self.body_labels.items()))
        os.rename(tmp_path, self.path)
def getLenp2(self):
        p1 = self.p1
        ret = p1.distance(self.p3)
        return ret