diff --git a/Octokit/Http/SimpleJsonSerializer.cs b/Octokit/Http/SimpleJsonSerializer.cs
index 081383d7..a022d141 100644
--- a/Octokit/Http/SimpleJsonSerializer.cs
+++ b/Octokit/Http/SimpleJsonSerializer.cs
@@ -30,14 +30,12 @@ namespace Octokit.Internal
             [SuppressMessage("Microsoft.Design", "CA1007:UseGenericsWhereAppropriate", Justification = "Need to support .NET 2")]
             protected override bool TrySerializeUnknownTypes(object input, out object output)
             {
-                if (input == null) throw new ArgumentNullException("input");
-                output = null;
-                Type type = input.GetType();
-                if (type.FullName == null)
-                    return false;
-                IDictionary<string, object> obj = new JsonObject();
-                IDictionary<string, ReflectionUtils.GetDelegate> getters = GetCache[type];
-                foreach (KeyValuePair<string, ReflectionUtils.GetDelegate> getter in getters)
+                Ensure.ArgumentNotNull(input, "input");
+
+                var type = input.GetType();
+                var jsonObject = new JsonObject();
+                var getters = GetCache[type];
+                foreach (var getter in getters)
                 {
                     if (getter.Value != null)
                     {
@@ -45,10 +43,10 @@ namespace Octokit.Internal
                         if (value == null)
                             continue;
 
-                        obj.Add(MapClrMemberNameToJsonFieldName(getter.Key), value);
+                        jsonObject.Add(MapClrMemberNameToJsonFieldName(getter.Key), value);
                     }
                 }
-                output = obj;
+                output = jsonObject;
                 return true;
             }