How to make the Pointshop NPC invincible

I’m looking for a way to make the Pointshop Vendor NPC invincible, what line of code should I add to do this?

I tried adding ‘npc:SetHealth(100000000)’ into the sv_pointshop.lua under the local npc = ents.Create(“npc_citizen”), but it’s made no change. What’s another way to do this, or is my method skewed?

This will make all npcs invulnerable to damage.

[lua]hook.Add(“ScaleNPCDamage”,“ScaleDamage”, function( npc, hitgroup, dmginfo )
dmginfo:ScaleDamage( 0 )
end)[/lua]

Otherwise, you can make the npc a scripted entity, and overwrite this function:
[lua]function ENT:OnTakeDamage()
return false;
end[/lua]

Thanks. The first one worked fine for me.