Help me fix plugins

Fatal error: Declaration of BattleRoyale\EntityManager::attack(pocketmine\event\entity\EntityDamageEvent $source) must be compatible with pocketmine\entity\Living::attack(pocketmine\event\entity\EntityDamageEvent $source): void in /storage/emulated/0/PocketMine-MP/plugins/BattleRoyale-master/src/BattleRoyale/EntityManager.php on line 60

on the console such error message

Below is the code of the EntityManager.php file

PHP:

<?php

namespace BattleRoyale;

use pocketmine\Player;
use pocketmine\entity\Living;
use pocketmine\network\mcpe\protocol\AddEntityPacket;
use pocketmine\event\entity\EntityDamageEvent;
use pocketmine\nbt\tag\CompoundTag;
use pocketmine\nbt\tag\ListTag;
use pocketmine\nbt\tag\DoubleTag;
use pocketmine\nbt\tag\FloatTag;

abstract class EntityManager extends Living {

    public $width = 1;

    public function attack(EntityDamageEvent $source){
        if($source->getCause() !== EntityDamageEvent::CAUSE_VOID){
            $source->setCancelled();
        }else{
            if($this->isAlive()){
                $this->close();
            }
        }
    }

    public function spawnTo(Player $player){
        $packet = new AddEntityPacket();
        $packet->type = static::NETWORK_ID;
        $packet->motion = $this->getMotion();
        $packet->position = $this->asVector3();
        $packet->entityRuntimeId = $this->getId();
        $packet->pitch = $this->pitch;
        $packet->yaw = $this->yaw;
        $packet->metadata = $this->getDataPropertyManager()->getAll();
        $player->dataPacket($packet);
        parent::spawnTo($player);
    }

    public static function getCompoundMotion(Player $player): CompoundTag{
        $data = new CompoundTag("", [
            new ListTag("Pos", array(
                new DoubleTag("", $player->getX()),
                new DoubleTag("", $player->getY() + $player->getEyeHeight()),
                new DoubleTag("", $player->getZ())
            )),
            new ListTag("Motion", array(
                new DoubleTag("", -sin($player->yaw / 180 * M_PI) * cos($player->pitch / 180 * M_PI)),
                new DoubleTag("", -sin($player->pitch / 180 * M_PI)),
                new DoubleTag("", cos($player->yaw / 180 * M_PI) * cos($player->pitch / 180 * M_PI))
            )),
            new ListTag("Rotation", array(
                new FloatTag("", $player->yaw),
                new FloatTag("", $player->pitch)
            ))
        ]);
        return $data;
    }
}

 

Add a : void return type declaration to the attack function.

 

I added as you said but still got errors maybe I put it wrong or can you write down any additional details (I use Google Translate to communicate so there is a wrong word for the word)

 

Replace this:

PHP:

public function attack(EntityDamageEvent $source){

with this

PHP:

public function attack(EntityDamageEvent $source) : void{

and

this

PHP:

public function spawnTo(Player $player){

with this

PHP:

public function spawnTo(Player $player) : void{

 

this is the plugins I downloaded the old api plugins is the api: 3.0.0-ALPHA12 I have upgraded to api 3.0.0 and there are too many errors here are the plugins I have fixed as you said but still have errors in the plugins below are the plugins I have correct but still have errors

can also fix plugins to work properly or outdated plugins
Here are the plugins I mentioned