LoL, man thanks, I don't understand how stupid I can be some times

But one thing I don't understand is why did you add
register_cvar("mp_god", "0") and why did you add "0" after amx_god as well?
What does this do?
Code:
#define set_user_godmode(%1,%2) set_pev(%1,pev_takedamage,%2*2)
#define get_user_godmode(%1) (pev(%1,pev_takedamage) )
I thought i would need to use fun bc set_user_godmode is ni the fun.inc
Sorry that I'm noob.