Python help can't figure out why unit test is failing

Hi I am new to python and I am having an issue figuring out what's wrong with my code and why the unit test is failing? Below is the code, unit test and error message when running the test:

legs = []
stomach = []
class Centipede(object):
    def __init__(self):

    def __str__(self):       
        return ','.join(self.stomach)

    def __call__(self,*args):
        [self.stomach.append(arg) for arg in args]
        #self.stomach.append(args)

    def __repr__(self):
        return ','.join(self.legs)

    def __setattr__(self, key, value):
        print("setting %s to %s" % (key, repr(value)))
        if key in ([]):
            self.legs.append(key)
            #self.__dict__[key] = value
            object.__setattr__(self, key,value)

Unit test code

import unittest
from centipede import Centipede

class TestBug(unittest.TestCase):

    def test_stomach(self):
        ralph = Centipede()
        ralph('chocolate')
        ralph('bbq')
        ralph('cookies')
        ralph('salad')
        self.assertEquals(ralph.__str__(), 'cho开发者_StackOverflow社区colate,bbq,cookies,salad')


    def test_legs(self):
        ralph = Centipede()
        ralph.friends = ['Steve', 'Daniel', 'Guido']
        ralph.favorite_show = "Monty Python's Flying Circus"
        ralph.age = '31'
        self.assertEquals(ralph.__repr__(),'<friends,favorite_show,age>' )

if __name__ == "__main__":
    unittest.main()

error message generated when running the test:

AttributeError: 'Centipede' object has no attribute 'legs'
AttributeError: 'Centipede' object has no attribute 'stomach'

Move the legs and stomach into the Centipede. (I have always wanted to say that :))

class Centipede(object): 
    def init(self):
        self.stomach=[]
        self.legs=[]

self.legs is never set before you use it. Are you sure you don't mean just "legs" without the "self" part since you have a global variable called legs that you're not using?

You have declared legs and stomach outside of the class - ralph doesn't know that they are supposed to belong to him.

Putting legs and stomach after the class line and indenting them the same amount as __init__ should start moving you forward.