Can keras.utils.Sequence return a triple?

I have a model where the inputs are X,Y,M. All of them are matrices. My custom loss function needs access to the Mask matrix so that I can do something like tf.square(y_true - y_pred*mask). All of my batches are generated by a class that inherits from keras.utils.Sequence.

All of the examples I have seen show the getitem method for the Sequence class returning x,y.
I need to return x,y,m. Is this legal? I’m trying to debug a problem and I need to understand if this basic assumption about the Sequence was valid?