modify the following python code to implement the Forward-Forward algorithm:

for i in range(N_LAYER):
    x_ = layer_norm(x, *params(f'blocks.{i}.ln1'))
    dx, state[i][:3] = time_mixing(x_, *state[i][:3], *params(f'blocks.{i}.att'))
    x = x + dx

    x_ = layer_norm(x, *params(f'blocks.{i}.ln2'))
    dx, state[i][3] = channel_mixing(x_, state[i][3], *params(f'blocks.{i}.ffn'))
    x = x + dx