public static function getInstance(DIContainer $container = null)
	{
		static $instance = null;

		if ( null === $instance ) {
			$instance = new static($container);
		}

		return $instance;
	}
public static function getInstance(DIContainer $container = null)
	{
		static $instance = null;

		if ( null === $instance ) {
			$instance = new static($container);
		}

		return $instance;
	}
public static function getInstance ( DIContainer $ container = null ) { static $ instance = null ; if ( null === $ instance ) { $ instance = new static ( $ container ) ; } return $ instance ; }
Returns instance of strategy manager.

@param DIContainer $container Dependency injection container.

@return self
Returns instance of strategy manager .