Overriding on_generated function of the vacuum mod

[Red_King_Cyclops]

I'm working on a mod that depends on vacuum. The vacuum mod has an on_generated function that simply replaces all air blocks with vacuum blocks above a certain y-height. For the mod I am making, there needs to be certain "y-levels" that contain air but are surrounded by vacuum "y-levels." To do this, should I override vacuum's on_generated function, or should I make a second on_generated function that replaces certain vacuum blocks with air blocks?

[Krock]

Registering a new on_generated callback would be the sane solution here. Another option would be to hijack the already registered callbacks and calling them manually before yours depending on the Y value, but I'd not recommend to do that unless you're forced to use plain Lua (no JIT).