Error: Property 'drawingController' cannot be found in forward class object 'xxxxx.swift'

[mshashank0]

Getting error while using "DrawingController" in swift class.
Using - Swift 4.1 & Xcode 10.1

[mshashank0]

I just need to add "@objc" before declaring property of "DrawingController" in my swift class
---@objc var drawingController: DrawingController? ----