I'm helping at puppy classes at the minute, and in every class there are 1 or 2 dogs who really struggle to focus in the class environment... so you're not alone.
As helpers we assist the owners with these dogs by trying to block their line of sight to the other dogs - and owners are encouraged to keep their attention through practicing the training or playing (depending on the dog!). This week one pup had a rawhide bone the owners were encouraging him to chew on during any down time and we barely heard a peep out of him (a young bouncy lab who had been on a fortnight's rest due to a problem with his leg!!!!). At the first class everyone is told to ensure they reward their dogs for paying them any positive attention during the puppy class (or for lying down calmly!) so that they find this just as rewarding as bouncing around!
He's not assertive, he's just excited and distracted by the environment...
Is there anyone who can go along to the classes with you, so one of you can be working with Pepper and the other listening to the instructions?? That way you will really get the most from the lessons, as it can be hard to listen and learn while trying to keep an over-excited pup occupied!!! Also try to sit somewhere where you don't have dogs both sides of you - that way you are limiting the distractions!!!
Either that or look to some 1 to 1 lessons, as Top Barks suggests!!