/**
  * Get the instance
  *
  * @return Yoast_GA_Dashboards
  */
 public static function get_instance()
 {
     if (is_null(self::$instance)) {
         self::$instance = new self();
     }
     return self::$instance;
 }
 /**
  * Construct on the dashboards class for GA
  *
  * @param int   $ga_profile_id
  * @param array $active_metrics
  * @param array $valid_metrics
  */
 public function __construct($ga_profile_id, $active_metrics, $valid_metrics)
 {
     $this->ga_profile_id = $ga_profile_id;
     $active_metrics = $this->filter_metrics_to_dimensions($active_metrics);
     $this->active_metrics = $active_metrics;
     add_filter('ga_dashboards_dimensions', array($this, 'filter_dimensions'), 10, 1);
     $this->options = Yoast_GA_Dashboards_Api_Options::get_instance();
     $this->init_shutdown_hook();
 }