Checkbutton Toggle mode function for idle game help

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:bust_in_silhouette: Asked By Iplayx

So I’m working on a rpg incremental
In this game the player can sent servant to kill the enemy for you.
This can be activated by pressing a checkbutton.
I have a var called servant amount which will determine how many servant i have.
If i have 0 servant I want it to be disabled
If i have 1 or more it will be enable and if i toggle it it will remove 1servant.(toggle =true)(on)
If toggle is false(off) i want to get back the servant that i gave so servant amount += 1

How can i set up this on a function: