Cacher is the code snippet organizer for pro developers

def generate_all_set(A, k):
    if k == 1:
        for i in A:
            yield (i, )
    else:
        for i in A:
            for j in generate_all_set(A, k - 1):
                yield (i, ) + j

def Perm(A, k, n):
    if k == n - 1:
        yield tuple(A[:n])
    else:
        for i in range(k, n):
            A[i], A[k] = A[k], A[i]
            yield from Perm(A, k+1, n)
            A[i], A[k]  = A[k], A[i]