 
 import Foundation
 
-class ConcurrentOperation: Operation
+open class ConcurrentOperation: Operation
 {
-    override var isAsynchronous: Bool {
+    override open var isAsynchronous: Bool {
         return true
     }
     

        }
    }
    
    override var isExecuting: Bool {
        return _executing
    }
    

        }
    }
    
    override open var isFinished: Bool {
        return _finished
    }
    
    override open func start()
    {
        _executing = true
        execute()
    }
    
    open func execute()
    {
        // Execute your async task here.
    }
    
    open func finish()
    {
        _executing = false
        _finished = true
