unload level crash

PHP:

 $level->unload()

crash:

Spoiler

Error: Call to a member function getName() on null
File: /src/pocketmine/level/Level__32bit
Line: 2634
Type: E_ERROR

Code:
[2625] return (int) $this->time;
[2626] }
[2627]
[2628] /**
[2629] * Returns the Level name
[2630] *
[2631] * @return string
[2632] */
[2633] public function getName(){
[2634] return $this->provider->getName();
[2635] }
[2636]
[2637] /**
[2638] * Returns the Level folder name
[2639] *
[2640] * @return string
[2641] */
[2642] public function getFolderName(){
[2643] return $this->folderName;
[2644] }

Backtrace:
#0 /src/pocketmine/Server__32bit(0): pocketmine\Server->crashDump()
#1 /src/pocketmine/Server__32bit(2355): pocketmine\level\Level->getName()
#2 /src/pocketmine/Server__32bit(2503): pocketmine\Server->checkTickUpdates()
#3 /src/pocketmine/Server__32bit(2306): pocketmine\Server->tick()
#4 /src/pocketmine/Server__32bit(2184): pocketmine\Server->tickProcessor()
#5 /src/pocketmine/Server__32bit(1784): pocketmine\Server->start()
#6 /src/pocketmine/PocketMine(464): pocketmine\Server->__construct()
#7 (1): ()
#8 (0): {main}()

PocketMine-MP version: 1.5dev #1255 [Protocol 27; API 1.12.0]
Git commit: 0000000000000000000000000000000000000000
uname -a: Windows NT MBW8 6.3 build 9200 (Windows 8.1 Business Edition) i586
PHP Version: 5.6.4
Zend version: 2.6.0
OS : WINNT, win

Loaded plugins:
DevTools 1.10.0 by PocketMine Team for API(s) 1.3.1
EssentialsPE 1.1.0 by LegendsOfMCPE Team for API(s) 1.12.0
MCG76_WorldEdit 0.5.2 by minecraftgenius76 for API(s) 1.8.0
PurePerms 1.1.6 by 64FF00 for API(s) 1.12.0
WorldEditArt 1.0.0_beta_dev_#048 by PEMapModder for API(s) 1.0.0
BedWars 1 by CreeperFace for API(s) 1.12.0

how can i fix this?

Try:

PHP:

 $this->getServer()->unloadLevel($lv->getName(),true);


Of course level must be loaded, so I suggest use try {}, like:

PHP:

try {
 $this->getServer()->unloadLevel($lv->getName(),true);
}
 catch (Exception $e){
 $this->getLogger()->notice($e);
}


It should be $server->unloadLevel($level, $force).

ok thx