this idea of class imbalance and unlabeled weekly supervised data sets so one characteristic of machine learning models and you know deep learning convolutional image classifiers is that class imbalance can really destroy the performance so for example if you're training a cat versus dog image classifier and you have 80% of your data your training data is cats and 20% its dogs your train model is going to want to predict cats it's going to be biased towards the imbalance data so in these weekly supervised data sets such