Pairing 2 chests into 1

I've been having trouble pairing two chests, and I have no clue what to do. It was working with one chest, but now has stopped. I have searched through the Chest.php and tried many ways with no success.

Main:

PHP:

public function onDeath(Death $event) {
$entity = $event->getEntity();
$lvl = $entity->getLevel();
if ($entity instanceof Player) {
$x = $entity->getX();
$y = $entity->getY();
$z = $entity->getZ();
$dchest = new Block(Block::CHEST);
$inventory = $entity->getInventory()->getContents();
$event->setDrops(array(Item::get(Item::AIR)));
$entity->getLevel()->setBlock(new Vector3($x, $y, $z), new Block(Block::CHEST), true, true);
$entity->getLevel()->setBlock(new Vector3($x-1, $y, $z), $dchest, true, true);
$nbt = new CompoundTag("", [new ListTag("Items", []), new StringTag("id", Tile::CHEST), new IntTag("x", $x), new IntTag("y", $y), new IntTag("z", $z)]);
$nbt->Items->setTagType(NBT::TAG_Compound);
$tile = Tile::createTile("Chest", $entity->getLevel()->getChunk($x >> 4, $z >> 4), $nbt);
$chest = $lvl->getTile(new Vector3($x, $y, $z));
$chest->getInventory()->setContents($inventory);
$other = $chest->getRight();
if($chest instanceof Chest){
if($chest->isPaired() === false){
$chest->pairWith($dchest);
}
}
}
}


Error:

Code:

[04:06:12] [Server thread/CRITICAL]: "Could not pass event 'pocketmine\event\player\PlayerDeathEvent' to 'TimeBombPE v1.0.0': Call to a member function isPaired() on null on TimeBomb\Main
[04:06:12] [Server thread/CRITICAL]: Error: "Call to a member function isPaired() on null" (EXCEPTION) in "/TimeBomb/src/TimeBomb/main" at line 69

The "Chest" you used... Is it pocketmine\block\Chest or pocketmine\tile\Chest?

Should I use tile?

Still having problems with making two single chests into one double chest.