To accomplish this and to allow you to observe the other dogs in class, it is helpful that your dog is comfortable in a crate during class. (wagitwithus.com)
If your pets are comfortable in crates or carriers, they will at least have a piece of their home environment with them. (sandiegopetsmagazine.com)
By this stage, the dog should be comfortable in the crate for short periods. (petsinlive.com)