My modified script doesn't work

I wanted to modify this script so that only the police could use this command, so I modified it like this.
But when I log into the server and use the command,
SCRIPT ERROR: @wk_delveh/client.lua:11: attempt to index a nil value (field ‘job’)
An error will appear. Restarting the script fixes it, but if I login again, it becomes unusable. What should I do?
script:[Release] Delete Vehicle Script [v1.1.0] (Updated 2020)