Fix some output format issues

Change-Id: I6eab9da1f0c4ff047b27c3d8c572d587a32d61ce
diff --git a/scripts/nbhelper/device.py b/scripts/nbhelper/device.py
index a88740b..94b03df 100644
--- a/scripts/nbhelper/device.py
+++ b/scripts/nbhelper/device.py
@@ -230,11 +230,12 @@
                     if not destination:
                         continue
 
-                    # If interface address is in destination subnet, we don't need this route
-                    if netaddr.IPNetwork(address).ip in netaddr.IPNetwork(destination):
-                        continue
+                    for dest_addr in destination.split(","):
 
-                    for dest_addr in destination.split():
+                        # If interface address is in destination subnet, we don't need this route
+                        if netaddr.IPNetwork(address).ip in netaddr.IPNetwork(dest_addr):
+                            continue
+
                         new_route = {
                             "to": dest_addr,
                             "via": str(netaddr.IPNetwork(reserved_ip["ip4"]).ip),