diff --git a/readme.md b/readme.md
index 5a05223..4dd72ec 100644
--- a/readme.md
+++ b/readme.md
@@ -324,7 +324,7 @@ classDiagram
         -io_buffer: IOBuffer
 
         +ResponseParser(io_buffer IOBuffer)
-        +parse(xml str) Union~Command, Entry~
+        +parse(xml str) Command | Entry
     }
 
     class Entry {