diff --git a/source/02_language_guide/16_Optional_Chaining.md b/source/02_language_guide/16_Optional_Chaining.md
index 2cd94a2f..aaf2609d 100755
--- a/source/02_language_guide/16_Optional_Chaining.md
+++ b/source/02_language_guide/16_Optional_Chaining.md
@@ -97,7 +97,7 @@ class Person {
 
 ```swift
 class Residence {
-    var rooms = [Room]()
+    var rooms: [Room] = []
     var numberOfRooms: Int {
         return rooms.count
     }