diff --git a/scripts/nbhelper/container.py b/scripts/nbhelper/container.py
index 2f3748a..397ee32 100644
--- a/scripts/nbhelper/container.py
+++ b/scripts/nbhelper/container.py
@@ -144,6 +144,11 @@
                 or ""
             )
 
+            # When prefix.routes is None, we will get the RouterIP from prefix instance
+            # And to output a normal format, we need to build as a list here.
+            if isinstance(routes, str):
+                routes = [{"ip": routes}]
+
             self.instances[prefix.data.description] = {
                 "domain": domain,
                 "subnet": prefix.subnet,