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 setPP(self, p1, p2):
        self.p1 = p1
        self.p2 = p2
        self.Tail = self.p1
        self.Head = self.p2
        self.length = math.sqrt(math.pow(self.p2.x-self.p1.x, 2)+math.pow(self.p2.y-self.p1.y,2))