Error Using 'augmentedImageDatastore class.

I am using the following matlab builtin example

openExample('nnet/TransferLearningUsingGoogLeNetExample')

when i run the

augimdsValidation = augmentedImageDatastore(inputSize(1:2),imdsValidation);

section it gives me the error please help

In class 'augmentedImageDatastore', the get method for Dependent property 'NumObservations' attempts to access the stored property value.  Dependent properties don't store a value