that is not done in the Netherlands. For cyclists you just point in the direction you’re going with the arm closest to that direction.This is taught to children at a young age.
For driving a car I was never taught hand signals, I suspect that if you drive while your lights aren’t working, you’ll get a fine if caught. Wikipedia says that when driving oldtimers, which often don’t have a cab, you just point in the direction you’re turning, same as on a bike.