Functional Obedience - No
If you have not yet looked at Functional Obedience - Yes, I suggest you look at that first.
First let us define punishment. Punishment defines the act of making a behaviour less likely to happen again. Its an emotionally charge term that makes us think of wooden spoons and belts. In our context, that is not the case.
The word "No" allows us to capture a snapshot in time to be able to punish that particular behaviour - not the dog, the behaviour.
The video has an excellent example in which I talk about a dog that seeks to get through a door. This will help you understand how to best use the signal "No" and its effect upon your dog.