--- a/mod_storage_memory/mod_storage_memory.lua	Thu Mar 30 21:12:14 2017 +0200
+++ b/mod_storage_memory/mod_storage_memory.lua	Thu Mar 30 23:33:45 2017 +0200
@@ -86,7 +86,7 @@
 	end
 	a[i] = v;
 	a[key] = i;
-	return true;
+	return key;
 end
 
 local function archive_iter (a, start, stop, step, limit, when_start, when_end, match_with)