I've owned dogs all my life. Never considered the need for "dog swimming lessons." When we are walking by creeks and rivers, or by the ocean, the dogs will jump in and sometimes they won't. I leave it up to them. When they do decide to jump in, they instinctively know how to swim in their dog way. They certainly do not need swimming lessons from humans.
Dogs also have no business being in swimming pools. Their hair will end up clogging the filters and the chlorine probably isn't the best thing for them.