src/Relations/Relation.php
protected function cache_single( $result, Model $model ) {

		$id = $this->saver->get_pk( $result );

		wp_cache_set( $model->get_pk(), $id, $this->get_cache_group() );
	}
protected function cache_single( $result, Model $model ) {

		$id = $this->saver->get_pk( $result );

		wp_cache_set( $model->get_pk(), $id, $this->get_cache_group() );
	}
Cache a single result.

@since 2.0

@param Model|mixed $result
@param Model       $model