Attepmt to compare boolean with number

[JakusPL]

I changed a sound to my Airboat gun and error start showing. This is my code:

167        if self.Owner:KeyReleased(IN_ATTACK) && (!self.Weapon:Clip1() <= 0) then
168	self:EmitSound("Airboat.FireGunRevDown")
169	end

and error:

[ERROR] addons/airboat gun swep v3/lua/weapons/swep_airboatgun_v3.lua:167: attempt to compare boolean with number
  1. unknown - addons/airboat gun swep v3/lua/weapons/swep_airboatgun_v3.lua:167

[Ott]

Typo.
(!self.Weapon:Clip1() <= 0)
should be
!(self.Weapon:Clip1() <= 0)