Crash when removing sign before plugin

[inxomnyaa]

When you remove the sign before the plugin calls setblock this crash happens

Fatal error: Call to a member function setBlockIdAt() on null in phar://C:/Users/Administrator/Desktop/Server/MinecraftPE/WolvesFortressIM/plugins/SignWarp_v1.5.1.phar/src/aliuly/signwarp/Main.php on line 180

Call Stack:
    0.0181     435968   1. {main}() C:\Users\Administrator\Desktop\Server\MinecraftPE\WolvesFortressIM\ClearSky_1.0dev.phar:0
    0.0213     430784   2. require_once('phar://C:/Users/Administrator/Desktop/Server/MinecraftPE/WolvesFortressIM/ClearSky_1.0dev.phar/src/pocketmine/PocketMine.php') C:\Users\Administrator\Desktop\Server\MinecraftPE\WolvesFortressIM\ClearSky_1.0dev.phar:1
    0.2630     573392   3. pocketmine\Server->__construct() phar://C:/Users/Administrator/Desktop/Server/MinecraftPE/WolvesFortressIM/ClearSky_1.0dev.phar/src/pocketmine/PocketMine.php:442
   20.3876   34460912   4. pocketmine\Server->start() phar://C:/Users/Administrator/Desktop/Server/MinecraftPE/WolvesFortressIM/ClearSky_1.0dev.phar/src/pocketmine/Server.php:1723
   20.4115   34477104   5. pocketmine\Server->tickProcessor() phar://C:/Users/Administrator/Desktop/Server/MinecraftPE/WolvesFortressIM/ClearSky_1.0dev.phar/src/pocketmine/Server.php:2130
  825.2790   73755600   6. pocketmine\Server->tick() phar://C:/Users/Administrator/Desktop/Server/MinecraftPE/WolvesFortressIM/ClearSky_1.0dev.phar/src/pocketmine/Server.php:2252
  825.3236   73888672   7. pocketmine\scheduler\ServerScheduler->mainThreadHeartbeat() phar://C:/Users/Administrator/Desktop/Server/MinecraftPE/WolvesFortressIM/ClearSky_1.0dev.phar/src/pocketmine/Server.php:2510
  825.4081   73889752   8. pocketmine\scheduler\TaskHandler->run() phar://C:/Users/Administrator/Desktop/Server/MinecraftPE/WolvesFortressIM/ClearSky_1.0dev.phar/src/pocketmine/scheduler/ServerScheduler.php:227
  825.4081   73889752   9. aliuly\signwarp\common\PluginCallbackTask->onRun() phar://C:/Users/Administrator/Desktop/Server/MinecraftPE/WolvesFortressIM/ClearSky_1.0dev.phar/src/pocketmine/scheduler/TaskHandler.php:130
  825.4081   73890112  10. aliuly\signwarp\Main->doBreakSign() phar://C:/Users/Administrator/Desktop/Server/MinecraftPE/WolvesFortressIM/plugins/SignWarp_v1.5.1.phar/src/aliuly/signwarp/common/PluginCallbackTask.php:48