[ArmaniMan]

Besides the concern articulated by others.

I always worry when someone is training my dog without me being there... how do you know what they are doing? They could easily stick a choke collar on your dog, use harsh leash corrections, etc. All things that can lead to physical and psychological problems for your yorkie.

I think it would be better to find someone to work with you in your home, just remember that they are teaching you to train your dog and most of the work falls to you in being consistent with the methods they show you!