oUF\elements\aura.lua:331: attempt to index field '?' (a nil value)

local Auras = CreateFrame("Frame", nil, self)
Auras:SetPoint("TOPLEFT", self, "BOTTOMLEFT", 0, -4)
Auras.initialAnchor = "TOPLEFT"
Auras["growth-x"] = "RIGHT"
Auras["growth-y"] = "DOWN"
Auras['spacing-x'] = 3
Auras['spacing-y'] = 3
Auras.numDebuffs = C.unitframes.num_target_debuffs
Auras.numBuffs = C.unitframes.num_target_buffs
Auras:SetHeight(500)
Auras:SetWidth(targetWidth)
Auras.size = 26
Auras.gap = true

self.Auras = Auras

Auras.showStealableBuffs = true