final public static function get_instance( array $setting = [] ) {
		$class_name = get_called_class();
		if ( ! isset( self::$instances[ $class_name ] ) ) {
			self::$instances[ $class_name ] = new $class_name( $setting );
		}

		return self::$instances[ $class_name ];
	}
final public static function get_instance( array $setting = [] ) {
		$class_name = get_called_class();
		if ( ! isset( self::$instances[ $class_name ] ) ) {
			self::$instances[ $class_name ] = new $class_name( $setting );
		}

		return self::$instances[ $class_name ];
	}
final public static function get_instance ( array $ setting = [ ] ) { $ class_name = get_called_class ( ) ; if ( ! isset ( self :: $ instances [ $ class_name ] ) ) { self :: $ instances [ $ class_name ] = new $ class_name ( $ setting ) ; } return self :: $ instances [ $ class_name ] ; }
Singleton initialize method

@param array $setting

@return static
Singleton initialize method