def add_dataset(self, key, values, color=None):
        d = dict(key=key, values=values)
        if color:
            d['color'] = color
        self.data.append(d)
If the user has viewing rights to the specified episode, returns that episode, otherwise
dataset/ETHPy150Open dimagi/commcare-hq/corehq/apps/reports/graph_models.py/LineChart.add_dataset--crossover with--dataset/ETHPy150Open viewfinderco/viewfinder/backend/db/episode.py/Episode.QueryIfVisible