public static final function instance(self $instance = null)
	{
		if( ! self::$_instance)
		{
			self::$_instance = ! is_null($instance)
				? $instance
				: new static(2);
		}
		return self::$_instance;
	}
public static final function instance(self $instance = null)
	{
		if( ! self::$_instance)
		{
			self::$_instance = ! is_null($instance)
				? $instance
				: new static(2);
		}
		return self::$_instance;
	}
public static final function instance ( self $ instance = null ) { if ( ! self :: $ _instance ) { self :: $ _instance = ! is_null ( $ instance ) ? $ instance : new static ( 2 ) ; } return self :: $ _instance ; }
The instance used by the static logging methods.

@param self $instance If provided, and called before any static logging calls have been made, the given $instance will be used by the static logging methods instead of creating a default one.

@see self::__callStatic
The instance used by the static logging methods .