centipede.py

class Centipede(object):

    def __init__(self):
        self.legs = list()
        self.stomach = list()
    
    def __call__(self, val):
        self.stomach.append(val)
    
    def __str__(self):
        return ",".join(self.stomach)
    
    def __setattr__(self, slot, val):
        self.__dict__[slot] = val
        self.legs.append(slot)