diff --git a/lib/wallet.py b/lib/wallet.py
index 4f207fb1..7422eab9 100644
--- a/lib/wallet.py
+++ b/lib/wallet.py
@@ -438,7 +438,7 @@ class Wallet:
 
         for addr in self.first_addresses.values():
             if addr not in o:
-                o += addr
+                o += [addr]
         return o