function backwardsOneToOneDescriptor(declaredFieldName, declaredFromModelName) {
    return {
        get() {
            const {
                session: { [declaredFromModelName]: DeclaredFromModel },
            } = this.getClass();

            return DeclaredFromModel.get({
                [declaredFieldName]: this.getId(),
            });
        },
        set() {
            throw new Error("Can't mutate a reverse one-to-one relation.");
        },
    };
}
Here we resolve 1-to-1 relationships starting at the model on which the
field was not installed. This means we need to find the instance of the
other model whose {@link module:fields.oneToOne|oneToOne} FK field contains the current model's primary key.

@param  {string} declaredFieldName - the name of the field referencing the current model.
@param  {string} declaredFromModelName - the name of the other model.