How to delete a topology type used in a user-defined collection (UDC) that was deleted? (4301603)

Drop the topology type and then recreate the user-defined collection using the same name, follow the steps below: 

1. Navigate to "user-defined Collections" dashboard, under Databases | (DB_Name) | Settings | Administration dashboard
2. Select the desired User Defined Collections (UDC) on this dashboard and click Delete
3. Click Save Changes
4. Ensure the UDC is deleted successfully
5. Navigate to Administration | Tooling | Script Console, query for 'DBSS_Custom_Query_Instance' to get the UDC name 
6. Under Administration | Tooling | Script Console | Scripts, run the below script to delete the 'Topology Object'
   customUdcOjbects = #! DBSS_Custom_Query_Instance where name='DBSS_Cust_xxxxxxxx_xxxxxx'#.topologyObjects;
   server.get("TopologyService").deleteObjects(customUdcOjbects as Set);
7. Under Administration | Tooling | Script Console | Scripts and run the below script to delete the 'Topology Type'
   def types = ["DBSS_Cust_xxxxxxxx_xxxxxx"]. collect {server.TopologyService.getType(it)} as Set
   server.TopologyService.removeTypes (types)
8. Both the scripts returns "null" as an output on the Script Console, it is expected
9. Check and see if the UDC is deleted from the dashboard.  Recreate the user-defined collection with the same name if needed.

def topologyService = server.get("TopologyService");
def Userdefinedcollections = #!DBSS_Custom_Query_Instance where name like 'DBSS_Cust_%'#.topologyObjects;
if ((Userdefinedcollections == null) || (Userdefinedcollections.isEmpty())) {
return "User defined collection does not exists!";
}
else {
for(item in Userdefinedcollections){
    println item
item = item.getUniqueId()
item = topologyService.getObject(item);
topologyService.deleteObject(item);
}
return "Done!";
}