Fix issues with Iterate.these

src/lib/Iterate.vala

@@ -23,7 +23,7 @@ namespace Invercargill.Iterate {
         return new Generators.Function<T>((owned)function);
     }
 
-    public static Enumerable<T> these<T>(T item1, ...) {
+    public static Enumerable<T> these<T>(owned T item1, ...) {
         var series = new Series<T>();
         var args = va_list();
         series.add(item1);
@@ -32,9 +32,9 @@ namespace Invercargill.Iterate {
             if(item == null) {
                 break;
             }
-            series.add(item);
+            series.add((owned)item);
         }
-        return series.seal();
+        return series.to_buffer().seal();
     }
 
     public static Enumerable<T> deferred<T>(owned Generators.DeferredDelegate<T> function) {