# generic_nested.py

# generic_nested.py

def do_next(gen):
    try:
        print(next(gen))
        return gen
    except:
        return 0

def nested_loops(n_or_indices, range_max=5):
    if isinstance(n_or_indices, list):
        indices = n_or_indices
        n = len(indices)
    else:
        n = n_or_indices
        indices = [0] * n

    while True:
        yield indices[:]

        for i in range(n - 1, -1, -1):
            if indices[i] < range_max - 1:
                indices[i] += 1
                break
            indices[i] = 0
        else:
            return

# Example usage with next and while loop:
gen1 = nested_loops(3)
while gen1:
    gen1 = do_next(gen1)

gen2 = nested_loops(4, 3)
while gen2:
    gen2 = do_next(gen2)

gen3 = nested_loops([0, 2, 1], 3)
while gen3:
    gen3 = do_next(gen3)