diff --git a/command.lua b/command.lua
index 281d84b..ffaa369 100644
--- a/command.lua
+++ b/command.lua
@@ -357,3 +357,22 @@ function tubelib.put_item(inv, listname, item)
 	end
 	return false
 end
+
+-- Get the number of items from the given ItemList.
+-- Returns nil if the number is not available.
+function tubelib.get_num_items(inv, listname, num)
+	if inv:is_empty(listname) then
+		return nil
+	end
+	local size = inv:get_size(listname)
+	for idx = 1, size do
+		local items = inv:get_stack(listname, idx)
+		if items:get_count() >= num then
+			local taken = items:take_item(num)
+			inv:set_stack(listname, idx, items)
+			return taken
+		end
+	end
+	return nil
+end
+
diff --git a/init.lua b/init.lua
index 2e57f19..4a35cd5 100644
--- a/init.lua
+++ b/init.lua
@@ -11,6 +11,7 @@
 	History:
 	2017-09-08  v0.01  first version
 	2017-09-12  v0.02  bugfix in tubelib.get_pos() and others
+	2017-09-21  v0.03  function get_num_items added
 
 ]]--
 
@@ -40,6 +41,8 @@ tubelib.knownNodes = {
 tubelib.legacyNodes = {
 	["default:chest_locked"] = true,
 	["default:chest"] = true,
+	["default:chest_locked_open"] = true,
+	["default:chest_open"] = true,
 	["default:furnace"] = true,
 	["default:furnace_active"] = true,
 }