problem with permutations

[cnb]

I am trying to translate this elegant Erlang-code for finding all the
permutations of a list.
I think it is the same function as is but it doesn't work in Python.
-- is upd in Python. It works as it should.

perms([]) -> [[]];
perms(L)  -> [[H|T] || H <- L, T <- perms(L--[H])].

def perms(lista):
    if lista == []:
        return [[]]
    else:
        for h in lista:
            return [([h]+[t]) for t in perms(upd(lista, h))]

def upd(lista, elem, acc=tuple([])):
    lista = tuple(lista)
    if lista == ():
        return list(acc)
    if lista[0] == elem:
        return list(acc + tuple(lista[1:]))
    else:
        return upd(lista[1:], elem, acc + tuple([lista[0]]))