 
     /// Conforms to `OperationWillFinishObserver`, executes the block
     public func willFinishOperation(operation: Operation, errors: [ErrorType]) {
-        block(operation, errors)
+        block(operation: operation, errors: errors)
+    }
+
+    /// Base OperationObserverType method
+    public func didAttachToOperation(operation: Operation) {
+        didAttachToOperation?(operation: operation)
     }
 }
 

 closure when the operation cancels.
 */
public struct CancelledObserver: OperationDidCancelObserver {
    public typealias BlockType = Operation -> Void

    private let block: BlockType

    /**
     Initialize the observer with a block.

    public func didFinishOperation(operation: Operation, errors: [ErrorType]) {
        didFinish?.didFinishOperation(operation, errors: errors)
    }

    /// Base OperationObserverType method
    public func didAttachToOperation(operation: Operation) {
        didAttachToOperation?(operation: operation)
    }
}


