Save info to the config file

Hello, im learning Pocketmine Plugin Development, the problem is that im trying to save info to the config file, but i don't know how to, i tried

PHP:

case 'setspawnp':
                    $spawn = $sender->getPosition();
                    $this->getServer()->getconfig()->set("spawn", $spawn);
                    $this->getServer()->save();
                    $sender->sendMessage(Color::GOLD."Arena Spawn Set");
                    break;

but "getconfig()" si not a function or something that is on pocket mine, i created the yaml file, and its like this:

PHP:

---
spawn: 0
positioncero: 0


im trying the plugin to save a position, but i don't really know how to or if im doing it good, but in a little part im confused.

Please help me, thanks.

sorry for being an ignorant

Hey!, thanks!!! i think my plugin my works, but the memory gets exhausted, is the problem of the code or of the server configuration?

should the plugin work??? i established the config file in a resources folder and then the other files and folders in a folder called "src", is that ok?

where can you help me with my code? i don't think i have an infinite loop, im kind of like new to this, can you help me?

But can you read the object back to $spawn like that?

Hmmm, its crashing, i fixed everything, but there must be an infinite loop... can you help me?

More code please?

Falk, please help