multiple inheritance

[newseater]

i don't know how to call methods of super classes when using multiple
inheritance. I've looked on the net but with no result :(

class a(object):
    def foo(self):
        print "a"

class b(object):
    def foo(self):
        print "a"

class c(a,b)
    def foo(self):
        super( ???? a).foo()
        super( ???? b).foo()

r = c()
r.foo()