def value(self, layer=None, view=None):
        raise NotImplementedError()
return an iteration of tuples of category and list of all words in instances of that category.
dataset/ETHPy150Open glue-viz/glue/glue/viewers/custom/qt/custom_viewer.py/FormElement.value--crossover with--dataset/ETHPy150Open japerk/nltk-trainer/train_classifier.py/category_words