diff --git a/src/pocketmine/level/format/io/BaseLevelProvider.php b/src/pocketmine/level/format/io/BaseLevelProvider.php
index 3a9a01be4..2022de406 100644
--- a/src/pocketmine/level/format/io/BaseLevelProvider.php
+++ b/src/pocketmine/level/format/io/BaseLevelProvider.php
@@ -150,6 +150,9 @@ abstract class BaseLevelProvider implements LevelProvider{
 		return $this->levelData;
 	}
 
+	/**
+	 * @return void
+	 */
 	public function saveLevelData(){
 		$nbt = new BigEndianNBTStream();
 		$buffer = $nbt->writeCompressed(new CompoundTag("", [
diff --git a/src/pocketmine/level/format/io/LevelProvider.php b/src/pocketmine/level/format/io/LevelProvider.php
index 5fa272c17..88e594def 100644
--- a/src/pocketmine/level/format/io/LevelProvider.php
+++ b/src/pocketmine/level/format/io/LevelProvider.php
@@ -72,6 +72,8 @@ interface LevelProvider{
 	 * @param int     $seed
 	 * @param string  $generator
 	 * @param array   $options
+	 *
+	 * @return void
 	 */
 	public static function generate(string $path, string $name, int $seed, string $generator, array $options = []);
 
@@ -119,6 +121,8 @@ interface LevelProvider{
 
 	/**
 	 * @param int $value
+	 *
+	 * @return void
 	 */
 	public function setTime(int $value);
 
@@ -129,6 +133,8 @@ interface LevelProvider{
 
 	/**
 	 * @param int $value
+	 *
+	 * @return void
 	 */
 	public function setSeed(int $value);
 
@@ -139,6 +145,8 @@ interface LevelProvider{
 
 	/**
 	 * @param Vector3 $pos
+	 *
+	 * @return void
 	 */
 	public function setSpawn(Vector3 $pos);
 
@@ -152,16 +160,22 @@ interface LevelProvider{
 	 * Sets the world difficulty.
 	 *
 	 * @param int $difficulty
+	 *
+	 * @return void
 	 */
 	public function setDifficulty(int $difficulty);
 
 	/**
 	 * Performs garbage collection in the level provider, such as cleaning up regions in Region-based worlds.
+	 *
+	 * @return void
 	 */
 	public function doGarbageCollection();
 
 	/**
 	 * Performs cleanups necessary when the level provider is closed and no longer needed.
+	 *
+	 * @return void
 	 */
 	public function close();
 
diff --git a/src/pocketmine/level/format/io/LevelProviderManager.php b/src/pocketmine/level/format/io/LevelProviderManager.php
index ca64a5c94..21f2602b3 100644
--- a/src/pocketmine/level/format/io/LevelProviderManager.php
+++ b/src/pocketmine/level/format/io/LevelProviderManager.php
@@ -44,6 +44,7 @@ abstract class LevelProviderManager{
 	/**
 	 * @param string $class
 	 *
+	 * @return void
 	 * @throws \InvalidArgumentException
 	 */
 	public static function addProvider(string $class){
diff --git a/src/pocketmine/level/format/io/leveldb/LevelDB.php b/src/pocketmine/level/format/io/leveldb/LevelDB.php
index 1a355062d..26df4ba57 100644
--- a/src/pocketmine/level/format/io/leveldb/LevelDB.php
+++ b/src/pocketmine/level/format/io/leveldb/LevelDB.php
@@ -102,7 +102,7 @@ class LevelDB extends BaseLevelProvider{
 	/** @var \LevelDB */
 	protected $db;
 
-	private static function checkForLevelDBExtension(){
+	private static function checkForLevelDBExtension() : void{
 		if(!extension_loaded('leveldb')){
 			throw new LevelException("The leveldb PHP extension is required to use this world format");
 		}
@@ -523,7 +523,7 @@ class LevelDB extends BaseLevelProvider{
 	 * @param CompoundTag[] $targets
 	 * @param string        $index
 	 */
-	private function writeTags(array $targets, string $index){
+	private function writeTags(array $targets, string $index) : void{
 		if(count($targets) > 0){
 			$nbt = new LittleEndianNBTStream();
 			$this->db->put($index, $nbt->write($targets));
diff --git a/src/pocketmine/level/format/io/region/McRegion.php b/src/pocketmine/level/format/io/region/McRegion.php
index 3aa089bf6..5077f8b19 100644
--- a/src/pocketmine/level/format/io/region/McRegion.php
+++ b/src/pocketmine/level/format/io/region/McRegion.php
@@ -333,6 +333,8 @@ class McRegion extends BaseLevelProvider{
 	 * @param int $chunkZ
 	 * @param int $regionX reference parameter
 	 * @param int $regionZ reference parameter
+	 *
+	 * @return void
 	 */
 	public static function getRegionIndex(int $chunkX, int $chunkZ, &$regionX, &$regionZ){
 		$regionX = $chunkX >> 5;
@@ -364,6 +366,8 @@ class McRegion extends BaseLevelProvider{
 	/**
 	 * @param int $regionX
 	 * @param int $regionZ
+	 *
+	 * @return void
 	 */
 	protected function loadRegion(int $regionX, int $regionZ){
 		if(!isset($this->regions[$index = Level::chunkHash($regionX, $regionZ)])){
diff --git a/src/pocketmine/level/format/io/region/RegionLoader.php b/src/pocketmine/level/format/io/region/RegionLoader.php
index 6b87a8a0d..0c313ed5e 100644
--- a/src/pocketmine/level/format/io/region/RegionLoader.php
+++ b/src/pocketmine/level/format/io/region/RegionLoader.php
@@ -87,6 +87,7 @@ class RegionLoader{
 	}
 
 	/**
+	 * @return void
 	 * @throws CorruptedRegionException
 	 */
 	public function open(){
@@ -188,6 +189,7 @@ class RegionLoader{
 	 * @param int    $z
 	 * @param string $chunkData
 	 *
+	 * @return void
 	 * @throws ChunkException
 	 * @throws \InvalidArgumentException
 	 */
@@ -220,6 +222,7 @@ class RegionLoader{
 	 * @param int $x
 	 * @param int $z
 	 *
+	 * @return void
 	 * @throws \InvalidArgumentException
 	 */
 	public function removeChunk(int $x, int $z){
@@ -256,6 +259,8 @@ class RegionLoader{
 	 * Writes the region header and closes the file
 	 *
 	 * @param bool $writeHeader
+	 *
+	 * @return void
 	 */
 	public function close(bool $writeHeader = true){
 		if(is_resource($this->filePointer)){
@@ -268,6 +273,7 @@ class RegionLoader{
 	}
 
 	/**
+	 * @return void
 	 * @throws CorruptedRegionException
 	 */
 	protected function loadLocationTable(){
@@ -329,7 +335,7 @@ class RegionLoader{
 		}
 	}
 
-	private function writeLocationTable(){
+	private function writeLocationTable() : void{
 		$write = [];
 
 		for($i = 0; $i < 1024; ++$i){
@@ -344,6 +350,8 @@ class RegionLoader{
 
 	/**
 	 * @param int $index
+	 *
+	 * @return void
 	 */
 	protected function writeLocationIndex($index){
 		fseek($this->filePointer, $index << 2);
@@ -352,6 +360,9 @@ class RegionLoader{
 		fwrite($this->filePointer, Binary::writeInt($this->locationTable[$index]->getTimestamp()), 4);
 	}
 
+	/**
+	 * @return void
+	 */
 	protected function createBlank(){
 		fseek($this->filePointer, 0);
 		ftruncate($this->filePointer, 8192); // this fills the file with the null byte