Determining value of detached guest house

[Christian Ramirez]

Alright Im a bit confused here on how much value this guest house can add to the property.

So the main house is a 2 bed 1 bath 856 sq ft with a detached  1 bed 1 bath guest house is the back yard measuring at 342 sq ft. This seller was renting the guest house at  $750 a month while living in the main house. 

The question is how do I determine the value of this guest house and how it affects ARV on this house when this is the only property in the area that has a detached guest house.