lightning module by Quasiduck, i cannot delete the lightning why?

the error is ReplicatedStorage.modules.LightningBolt:156: table index is nil

however my lightning bolt exists in it.

the section that the error occurs.

this section

function LightningBolt:Destroy()
    ActiveBranches[self._RefIndex] = nil

    for i = 1, #self._Parts do
        LightningCache:ReturnPart(self._Parts[i])
    end

    self = nil
end

local BoltPart = Instance.new("Part") --Template primitive that will make up the entire bolt
BoltPart.TopSurface, BoltPart.BottomSurface = 0, 0
BoltPart.Anchored, BoltPart.CanCollide = true, false
BoltPart.Locked, BoltPart.CastShadow = true, false
BoltPart.CanTouch, BoltPart.CanQuery = false, false
BoltPart.Shape = "Cylinder"
BoltPart.Name = "BoltPart"
BoltPart.Material = Enum.Material.Neon
BoltPart.Color = Color3.new(1, 1, 1)
BoltPart.Transparency = 1

local PartCache = require(script.Parent:WaitForChild("PartCache"))
local LightningCache = PartCache.new(BoltPart, PARTS_IN_CACHE)
LightningCache:SetCacheParent(parent)

--*

local function CubicBezier(PercentAlongBolt, p0, p1, p2, p3)
    return p0 * (1 - PercentAlongBolt) ^ 3
        + p1 * 3 * PercentAlongBolt * (1 - PercentAlongBolt) ^ 2
        + p2 * 3 * (1 - PercentAlongBolt) * PercentAlongBolt ^ 2
        + p3 * PercentAlongBolt ^ 3
end


local xInverse = CFrame.lookAt(Vector3.new(), Vector3.new(1, 0, 0)):inverse()
local offsetAngle = math.cos(math.rad(90))

local ActiveBranches = {} --Contains all LightningBolt instances

local LightningBolt = {} --Define new class
LightningBolt.__type = "LightningBolt"
LightningBolt.__index = LightningBolt

--Small tip: You don't need to use actual Roblox Attachments below. You can also create "fake" ones as follows:
--[[
    local A1, A2 = {}, {}
    A1.WorldPosition, A1.WorldAxis = chosenPos1, chosenAxis1
    A2.WorldPosition, A2.WorldAxis = chosenPos2, chosenAxis2
    local NewBolt = LightningBolt.new(A1, A2, 40)
--]]

function LightningBolt.new(Attachment0, Attachment1, PartCount)
    local self = setmetatable({}, LightningBolt)
    PartCount = PartCount or 30

    --*Main (default) Properties--

    --Bolt Appearance Properties

    self.Enabled = true --Hides bolt without removing any parts when false
    self.Attachment0, self.Attachment1 = Attachment0, Attachment1 --Bolt originates from Attachment0 and ends at Attachment1
    self.CurveSize0, self.CurveSize1 = 0, 0 --Works similarly to roblox beams. See https://dk135eecbplh9.cloudfront.net/assets/blt160ad3fdeadd4ff2/BeamCurve1.png
    self.MinRadius, self.MaxRadius = 0, 2.4 --Governs the amplitude of fluctuations throughout the bolt
    self.Frequency = 1 --Governs the frequency of fluctuations throughout the bolt. Lower this to remove jittery-looking lightning
    self.AnimationSpeed = 7 --Governs how fast the bolt oscillates (i.e. how fast the fluctuating wave travels along bolt)
    self.Thickness = 1 --The thickness of the bolt
    self.MinThicknessMultiplier, self.MaxThicknessMultiplier = 0.2, 1 --Multiplies Thickness value by a fluctuating random value between MinThicknessMultiplier and MaxThicknessMultiplier along the Bolt

    --Bolt Kinetic Properties

    --[[
        Allows for fading in (or out) of the bolt with time. Can also create a "projectile" bolt
        Recommend setting AnimationSpeed to 0 if used as projectile (for better aesthetics)
        Works by passing a "wave" function which travels from left to right where the wave height represents opacity (opacity being 1 - Transparency)
        See https://www.desmos.com/calculator/hg5h4fpfim to help customise the shape of the wave with the below properties
    --]]
    self.MinTransparency, self.MaxTransparency = 0, 1
    self.PulseSpeed = 2 --Bolt arrives at Attachment1 1/PulseSpeed seconds later
    self.PulseLength = 1000000
    self.FadeLength = 0.2
    self.ContractFrom = 0.5 --Parts shorten or grow once their Transparency exceeds this value. Set to a value above 1 to turn effect off. See https://imgur.com/OChA441

    --Bolt Color Properties

    self.Color = Color3.new(1, 1, 1) --Can be a Color3 or ColorSequence
    self.ColorOffsetSpeed = 3 --Sets speed at which ColorSequence travels along Bolt

    --*

    --*Advanced Properties--

    --[[
        Allows you to pass a custom space curve for the bolt to be defined along
        Constraints: 
            -First input passed must be a parameter representing PercentAlongBolt between values 0 and 1
        Example: self.SpaceCurveFunction = VivianiCurve(PercentAlongBolt)
    --]]
    self.SpaceCurveFunction = CubicBezier

    --[[
        Allows you to pass a custom opacity profile which controls the opacity along the bolt
        Constraints: 
            -First input passed must be a parameter representing PercentAlongBolt between values 0 and 1
            -Second input passed must be a parameter representing TimePassed since instantiation 
        Example: self.OpacityProfileFunction = MovingSineWave(PercentAlongBolt, TimePassed)
        Note: You may want to set self.ContractFrom to a value above 1 if you pass a custom opacity profile as contraction was designed to work with DiscretePulse
    --]]
    self.OpacityProfileFunction = DiscretePulse

    --[[
        Allows you to pass a custom radial profile which controls the radius of control points along the bolt
        Constraints: 
            -First input passed must be a parameter representing PercentAlongBolt between values 0 and 1
    --]]
    self.RadialProfileFunction = ExtrudeCenter
    --*

    --! Private vars are prefixed with an underscore (e.g. self._Parts) and should not be changed manually

    self._Parts = {} --The BoltParts which make up the Bolt

    for i = 1, PartCount do
        self._Parts[i] = LightningCache:GetPart()
    end

    self._PartsHidden = false
    self._DisabledTransparency = 1
    self._StartT = clock()
    self._RanNum = math.random() * 100
    self._RefIndex = #ActiveBranches + 1

    ActiveBranches[self._RefIndex] = self

    return self
end

function LightningBolt:Destroy()
    ActiveBranches[self._RefIndex] = nil

    for i = 1, #self._Parts do
        LightningCache:ReturnPart(self._Parts[i])
    end

    self = nil
end

--Calls Destroy() after TimeLength seconds where a dissipating effect takes place in the meantime
function LightningBolt:DestroyDissipate(TimeLength, Strength)
    TimeLength = TimeLength or 0.2
    Strength = Strength or 0.5
    local DissipateStartT = clock()
    local start, mid, goal = self.MinTransparency, self.ContractFrom, self.ContractFrom
        + 1 / (#self._Parts * self.FadeLength)
    local StartRadius = self.MaxRadius
    local StartMinThick = self.MinThicknessMultiplier
    local DissipateLoop

    DissipateLoop = RunService.Heartbeat:Connect(function()
        local TimeSinceDissipate = clock() - DissipateStartT
        self.MinThicknessMultiplier = StartMinThick + (-2 - StartMinThick) * TimeSinceDissipate / TimeLength

        if TimeSinceDissipate < TimeLength * 0.4 then
            local interp = (TimeSinceDissipate / (TimeLength * 0.4))
            self.MinTransparency = start + (mid - start) * interp
        elseif TimeSinceDissipate < TimeLength then
            local interp = ((TimeSinceDissipate - TimeLength * 0.4) / (TimeLength * 0.6))
            self.MinTransparency = mid + (goal - mid) * interp
            self.MaxRadius = StartRadius * (1 + Strength * interp)
            self.MinRadius = self.MinRadius + (self.MaxRadius - self.MinRadius) * interp
        else
            --Destroy Bolt
            local TimePassed = clock() - self._StartT
            local Lifetime = (self.PulseLength + 1) / self.PulseSpeed

            if TimePassed < Lifetime then --prevents Destroy()ing twice
                self:Destroy()
            end

            --Disconnect Loop
            DissipateLoop:Disconnect()
            DissipateLoop = nil
        end
    end)
end

function LightningBolt:_UpdateGeometry(
    BPart,
    PercentAlongBolt,
    TimePassed,
    ThicknessNoiseMultiplier,
    PrevPoint,
    NextPoint
)
    --Compute opacity for this particular section
    local MinOpa, MaxOpa = 1 - self.MaxTransparency, 1 - self.MinTransparency
    local Opacity = self.OpacityProfileFunction(
        PercentAlongBolt,
        TimePassed,
        self.PulseSpeed,
        self.PulseLength,
        self.FadeLength,
        MinOpa,
        MaxOpa
    )

    --Compute thickness for this particular section
    local Thickness = self.Thickness * ThicknessNoiseMultiplier * Opacity
    Opacity = Thickness > 0 and Opacity or 0

    --Compute + update sizing and orientation of this particular section
    local contractf = 1 - self.ContractFrom
    local PartsN = #self._Parts
    if Opacity > contractf then
        BPart.Size = Vector3.new((NextPoint - PrevPoint).Magnitude, Thickness, Thickness)
        BPart.CFrame = CFrame.lookAt((PrevPoint + NextPoint) * 0.5, NextPoint) * xInverse
        BPart.Transparency = 1 - Opacity
    elseif Opacity > contractf - 1 / (PartsN * self.FadeLength) then
        local interp = (1 - (Opacity - (contractf - 1 / (PartsN * self.FadeLength))) * PartsN * self.FadeLength)
            * (PercentAlongBolt < TimePassed * self.PulseSpeed - 0.5 * self.PulseLength and 1 or -1)
        BPart.Size = Vector3.new((1 - math.abs(interp)) * (NextPoint - PrevPoint).Magnitude, Thickness, Thickness)
        BPart.CFrame = CFrame.lookAt(
            PrevPoint + (NextPoint - PrevPoint) * (math.max(0, interp) + 0.5 * (1 - math.abs(interp))),
            NextPoint
        )
            * xInverse
        BPart.Transparency = 1 - Opacity
    else
        BPart.Transparency = 1
    end
end

function LightningBolt:_UpdateColor(BPart, PercentAlongBolt, TimePassed)
    if typeof(self.Color) == "Color3" then
        BPart.Color = self.Color
    else --ColorSequence
        local t1 = (self._RanNum + PercentAlongBolt - TimePassed * self.ColorOffsetSpeed) % 1
        local keypoints = self.Color.Keypoints
        for i = 1, #keypoints - 1 do
            if keypoints[i].Time < t1 and t1 < keypoints[i + 1].Time then
                BPart.Color = keypoints[i].Value:lerp(
                    keypoints[i + 1].Value,
                    (t1 - keypoints[i].Time) / (keypoints[i + 1].Time - keypoints[i].Time)
                )
                break
            end
        end
    end
end

function LightningBolt:_Disable()
    self.Enabled = false
    for _, BPart in ipairs(self._Parts) do
        BPart.Transparency = self._DisabledTransparency
    end
end


    debug.profileend()
end)

return LightningBolt

thankyou in advance