/**
  * Function used to create instance of class.
  */
 public static function instance()
 {
     if (!isset(self::$instance)) {
         self::$instance = new Easy_Real_Estate_Post_Types();
     }
     return self::$instance;
 }
 /**
  * This function fires on activation and flushes rewrite rules
  */
 function activate()
 {
     Easy_Real_Estate_Post_Types::init();
     // Registered post types must be added before flushing rewrite rules on activation
     flush_rewrite_rules();
 }