Bukkit

iniciar_blackmarket:
command: /blackmarketstart
type: RUN_CONSOLE
runcmd:
- axda start test
- axda start test1
- axda start test2
- npc select Pirata
- npc moveto -27.4 115 -28.72
- $delay$
- npc despawn
- axda stop test
- axda stop test1
- axda stop test2
delaytimer: 40
register: true

I created this command and it works correctly, but it returns this information.

/blackmarketstart
[11:14:16 INFO]: [Mycmd] The command blackmarketstart returns null. Fix it.
[11:14:16 INFO]: [Mycmd] The command blackmarketstart returns null. Fix it.
[11:14:16 INFO]: [Mycmd] The command blackmarketstart returns null. Fix it.

how do I fix this problem of returning null values