flatten nested

flatten.swift

   var returnList = [Int]()
    public func separateArray(_ ar:[Any]) {
        for li in ar {
            if li is Int {
                returnList.append(li as! Int)
            }else{
                for element in li as! Array<Any> {
                    if element is Int {
                        returnList.append(element as! Int)
                    }else{
                        separateArray(element as! Array<Any>)
                        
                    }
                }

            }
            
        }
    }

    separateArray([[1,[1,3]],2,[1,1]])
    print(returnList) //"[1, 1, 3, 2, 1, 1]"