diff --git a/Deque/Deque-Simple.swift b/Deque/Deque-Simple.swift
index f4f5f0409..fc0fcb2b2 100644
--- a/Deque/Deque-Simple.swift
+++ b/Deque/Deque-Simple.swift
@@ -21,7 +21,7 @@ public struct Deque<T> {
   }
 
   public mutating func enqueueFront(_ element: T) {
-    array.insert(element, atIndex: 0)
+    array.insert(element, at: 0)
   }
 
   public mutating func dequeue() -> T? {
diff --git a/Deque/Deque.playground/Contents.swift b/Deque/Deque.playground/Contents.swift
index df9b57a5e..9e7b22c02 100644
--- a/Deque/Deque.playground/Contents.swift
+++ b/Deque/Deque.playground/Contents.swift
@@ -1,10 +1,5 @@
 //: Playground - noun: a place where people can play
 
-// last checked with Xcode 9.0b4
-#if swift(>=4.0)
-print("Hello, Swift 4!")
-#endif
-
 public struct Deque<T> {
   private var array = [T]()
 
diff --git a/Deque/README.markdown b/Deque/README.markdown
index fda1de5f8..f3172e16e 100644
--- a/Deque/README.markdown
+++ b/Deque/README.markdown
@@ -23,7 +23,7 @@ public struct Deque<T> {
   }
 
   public mutating func enqueueFront(_ element: T) {
-    array.insert(element, atIndex: 0)
+    array.insert(element, at: 0)
   }
 
   public mutating func dequeue() -> T? {