This will cause an index error if the sample does not exist. This resource should subclass [this class](https://github.com/cbmi/varify/blob/variant-sets/varify/samples/resources.py#L50-L71) which gives you the two methods for enforcing access to the sample and getting (and caching) the sample instance given a primary key. Once you subclass, you need to add [this `is_not_found` method](https://github.com/cbmi/varify/blob/variant-sets/varify/samples/resources.py#L82-L83) to handle 404s.