'for' limit必须是一个数字 LUA错误

所以，我得到了一个看起来像这样的错误：[ERROR] addons/itemstore/lua/itemstore/lua/itemsure/vgui/container.lua:43 'for' limit必须是一个数字

这是container.lua

local PANEL = {}

AccessorFunc( PANEL, "ContainerID", "ContainerID" )
AccessorFunc( PANEL, "Rows", "Rows" )
AccessorFunc( PANEL, "Columns", "Columns" )

function PANEL:Init()
    self.Items = {}

    table.insert( itemstore.containers.Panels, self )
end

function PANEL:Refresh()
    local container = itemstore.containers.Get( self:GetContainerID() )
    if ( container ) then
        for i = 1, container.Size do
            if ( not self.Items[ i ] ) then
                self.Items[ i ] = self:Add( "ItemStoreSlot" )
            end

            local panel = self.Items[ i ]
            panel:SetItem( container:GetItem( i ) )
            panel:SetContainerID( self:GetContainerID() )
            panel:SetSlot( i )
            panel:InvalidateLayout()
        end

        self:InvalidateLayout()
    end
end

function PANEL:SetContainerID( containerid )
    self.ContainerID = containerid
    self:Refresh()
end

function PANEL:PerformLayout()
    self:SetSpaceX( 1 )
    self:SetSpaceY( 1 )

    local container = itemstore.containers.Get( self:GetContainerID() )
    if ( container ) then
        for i = 1, container.Size do
            local panel = self.Items[ i ]

            if ( panel ) then
                panel:SetSize( unpack( itemstore.config.SlotSize ) )
            end
        end
    end

    self.BaseClass.PerformLayout( self )
end

vgui.Register( "ItemStoreContainer", PANEL, "DIconLayout" )

有什么解决方案吗？我想不出任何办法，因为我认为它应该正常工作？