diff --git a/capsulflask/hub_model.py b/capsulflask/hub_model.py
index 375bb9f..73f60f5 100644
--- a/capsulflask/hub_model.py
+++ b/capsulflask/hub_model.py
@@ -228,8 +228,8 @@ class CapsulFlaskHub(VirtualizationInterface):
         # no need to do anything here since if it cant be parsed then generic_operation will handle it.
         pass
       
+    assigned_hosts_string = ", ".join(assigned_hosts)
     if number_of_assigned != 1:
-      assigned_hosts_string = ", ".join(assigned_hosts)
       raise ValueError(f"expected create capsul operation {operation_id} to be assigned to one host, it was assigned to {number_of_assigned} ({assigned_hosts_string})")
     if error_message != "":
       raise ValueError(f"create capsul operation {operation_id} on {assigned_hosts_string} failed with {error_message}")