/**
  * Records landing page & non landing page impression
  * @param $post_id
  * @param string $post_type
  * @param int $variation_id
  */
 public static function record_impression($post_id, $post_type = 'landing-page', $variation_id = 0)
 {
     /* If Landing Page Post Type */
     if ($post_type == 'landing-page') {
         $impressions = Landing_Pages_Variations::get_impressions($post_id, $variation_id);
         $impressions++;
         Landing_Pages_Variations::set_impressions_count($post_id, $variation_id, $impressions);
     } else {
         $impressions = Inbound_Content_Statistics::get_impressions_count($post_id);
         $impressions++;
         Inbound_Content_Statistics::set_impressions_count($post_id, 0, $impressions);
     }
 }