/**
  *		@singleton method used to instantiate class object
  *		@access public
  *		@return EE_Network_Config instance
  */
 public static function instance()
 {
     // check if class object is instantiated, and instantiated properly
     if (self::$_instance === NULL or !is_object(self::$_instance) or !self::$_instance instanceof EE_Network_Config) {
         self::$_instance = new self();
     }
     return self::$_instance;
 }