MainLogger can now have debug level disabled

src/pocketmine/metadata/LevelMetadataStore.php

@@ -29,6 +29,7 @@ class LevelMetadataStore extends MetadataStore{
 		if(!($level instanceof Level)){
 			throw new \InvalidArgumentException("Argument must be a Level instance");
 		}
+
 		return strtolower($level->getName()) . ":" . $metadataKey;
 	}
 }