python: hur komma åt alla attribut i en instance-lista?

class Bil:
    def __init__(self,model,price):
        self.model=model
        self.price=price
    def __cmp__(self,other): # list.sort is going to call this overloaded method. Making it possible to sort instances of this class
        if self.price<other.price: return -1
        if self.price==other.price: return 0
        if self.price>other.price: return 1


bilar=[Bil("Volvo",2000),Bil("Saab",3000),Bil("Skoda",500),Bil("BMW",10000)]
bilar.sort()
bilar.reverse()
for bil in bilar:
    print bil.model+":",str(bil.price)+" sek"

bilar.sort(key=lambda bil: bil.pris, reverse=True)

priser = [bil.pris for bil in bilar]