crash

[ghost]

i have set 3 arenas in the same world, sometimes when all 3 arenas are in-game and a player joins the queue the server crashes.

Error: Return value of robske_110\TTT\Game\Game::getArena() must be an instance of robske_110\TTT\Game\Arena, null returned

File: plugins/TicTacToe-dev/src/robske_110/TTT/Game/Game
Line: 201
Type: TypeError

THIS CRASH WAS CAUSED BY A PLUGIN
BAD PLUGIN: TicTacToe v1.0.0-InDev-alpha1-pre

Code:
[192] 		var_dump($this->arena);
[193] 		throw new \Exception("getOpponent: failed");*/
[194] 		return null;
[195] 	}
[196] 
[197]     /**
[198]      * @return Arena
[199]      */
[200] 	public function getArena(): Arena{
[201] 		return $this->arena;
[202] 	}
[203] 	
[204] 	/**
[205] 	 * @param Player $player
[206] 	 */
[207] 	public function addPlayer(Player $player){
[208] 		$this->players[$player->getId()] = [$player, false];
[209] 	}
[210] 	
[211] 	/**

Backtrace:
#0 plugins/TicTacToe-dev/src/robske_110/TTT/Game/GameManager(67): robske_110\TTT\Game\Game->getArena()
#1 plugins/TicTacToe-dev/src/robske_110/TTT/PlayerManager(95): robske_110\TTT\Game\GameManager->startGame(object robske_110\TTT\Game\Game)
#2 plugins/TicTacToe-dev/src/robske_110/TTT/PlayerManager(67): robske_110\TTT\PlayerManager->startGame(integer 511)
#3 plugins/TicTacToe-dev/src/robske_110/TTT/TicTacToe(199): robske_110\TTT\PlayerManager->addPlayer(integer 511)
#4 src/pocketmine/command/PluginCommand(54): robske_110\TTT\TicTacToe->onCommand(object pocketmine\Player, object pocketmine\command\PluginCommand, string[7] tttjoin, array[0])
#5 src/pocketmine/command/SimpleCommandMap(248): pocketmine\command\PluginCommand->execute(object pocketmine\Player, string[7] tttjoin, array[0])
#6 src/pocketmine/Server(1807): pocketmine\command\SimpleCommandMap->dispatch(object pocketmine\Player, string[7] tttjoin)
#7 plugins/Festival-stable/src/genboy/Festival/Festival(3009): pocketmine\Server->dispatchCommand(object pocketmine\Player, string[7] tttjoin)
#8 plugins/Festival-stable/src/genboy/Festival/Festival(2910): genboy\Festival\Festival->runAreaEvent(object genboy\Festival\Area, object pocketmine\event\player\PlayerMoveEvent, string[5] enter)
#9 plugins/Festival-stable/src/genboy/Festival/Festival(1394): genboy\Festival\Festival->enterArea(object genboy\Festival\Area, object pocketmine\event\player\PlayerMoveEvent)
#10 src/pocketmine/plugin/MethodEventExecutor(42): genboy\Festival\Festival->onMove(object pocketmine\event\player\PlayerMoveEvent)
#11 src/pocketmine/plugin/RegisteredListener(80): pocketmine\plugin\MethodEventExecutor->execute(object genboy\Festival\Festival, object pocketmine\event\player\PlayerMoveEvent)
#12 src/pocketmine/event/Event(88): pocketmine\plugin\RegisteredListener->callEvent(object pocketmine\event\player\PlayerMoveEvent)
#13 src/pocketmine/Player(1594): pocketmine\event\Event->call()
#14 src/pocketmine/Player(1702): pocketmine\Player->processMovement(integer 1)
#15 src/pocketmine/level/Level(844): pocketmine\Player->onUpdate(integer 23774)
#16 src/pocketmine/level/Level(777): pocketmine\level\Level->actuallyDoTick(integer 23774)
#17 src/pocketmine/Server(2256): pocketmine\level\Level->doTick(integer 23774)
#18 src/pocketmine/Server(2387): pocketmine\Server->checkTickUpdates(integer 23774, double 1587513141.7964)
#19 src/pocketmine/Server(2143): pocketmine\Server->tick()
#20 src/pocketmine/Server(1990): pocketmine\Server->tickProcessor()
#21 src/pocketmine/Server(1584): pocketmine\Server->start()
#22 src/pocketmine/PocketMine(273): pocketmine\Server->__construct(object BaseClassLoader, object pocketmine\utils\MainLogger, string[47] /home/minecraft/multicraft/servers/server22957/, string[55] /home/minecraft/multicraft/servers/server22957/plugins/)
#23 src/pocketmine/PocketMine(296): pocketmine\server()
#24 (11): require(string[113] phar:///home/minecraft/multicraft/jar/versions/PocketMine/PocketMine-MP-3.12.0.p)

PocketMine-MP version: 3.12.0 [Protocol 390]```