--- a/util/stanza.lua	Fri Jun 08 16:15:32 2018 +0200
+++ b/util/stanza.lua	Fri Jun 08 17:04:47 2018 +0200
@@ -135,7 +135,7 @@
 end
 
 function stanza_mt:add_direct_child(child)
-	if type(child) == "table" then
+	if is_stanza(child) then
 		t_insert(self.tags, child);
 	end
 	t_insert(self, child);