1 files changed, 1 insertions, 1 deletions
diff --git a/src/DotNetOpenAuth.OpenId.Provider/OpenId/Messages/CheckAuthenticationResponseProvider.cs b/src/DotNetOpenAuth.OpenId.Provider/OpenId/Messages/CheckAuthenticationResponseProvider.cs
index c187d5e..f69de5e 100644
--- a/src/DotNetOpenAuth.OpenId.Provider/OpenId/Messages/CheckAuthenticationResponseProvider.cs
+++ b/src/DotNetOpenAuth.OpenId.Provider/OpenId/Messages/CheckAuthenticationResponseProvider.cs
@@ -7,11 +7,11 @@
 namespace DotNetOpenAuth.OpenId.Messages {
 	using System;
 	using System.Collections.Generic;
-	using System.Diagnostics.Contracts;
 	using System.Linq;
 	using System.Text;
 	using DotNetOpenAuth.OpenId.ChannelElements;
 	using DotNetOpenAuth.OpenId.Provider;
+	using Validation;
 
 	/// <summary>
 	/// The check_auth response message, as it is seen by the OpenID Provider.