Keras Data Generator, show generated input and output

Question

I implemented an own simple datagenerator based on https://stanford.edu/~shervine/blog/keras-how-to-generate-data-on-the-fly My datagenerator uses as input and as output images. Now I want to see the images, which the generator will use. Does anyone know, how to get them?

datagen = DataGenerator(ids_training, input_dir, output_dir, **params)

X,y = datagen.next()

The datagen.next() doesn't work. I get the error "'dataGenerator' object has no attribute 'next'"

Thanks in advance!