diff --git a/src/main/kotlin/ru/dbotthepony/mc/otm/container/ContainerHelpers.kt b/src/main/kotlin/ru/dbotthepony/mc/otm/container/ContainerHelpers.kt
index 84b25bfe9..74cd6669f 100644
--- a/src/main/kotlin/ru/dbotthepony/mc/otm/container/ContainerHelpers.kt
+++ b/src/main/kotlin/ru/dbotthepony/mc/otm/container/ContainerHelpers.kt
@@ -44,7 +44,7 @@ val Container.slotRange: IntRange2Set get() {
 	return IntRange2Set.openEnded(0, containerSize)
 }
 
-fun Container.addItem(stack: ItemStack, simulate: Boolean, slots: IntSortedSet = slotRange): ItemStack {
+fun Container.addItem(stack: ItemStack, simulate: Boolean, slots: IntSet = slotRange): ItemStack {
 	return IEnhancedContainer.wrap(this).addItem(stack, simulate, slots)
 }