def keys(self):
        raise NotImplementedError("This method must be implemented!")
Updates the learner's information based on the unit they have chosen.
dataset/ETHPy150Open 64studio/pdk/pdk/xml_legacy/sax/saxlib.py/Attributes.keys--crossover with--dataset/ETHPy150Open heiskr/sagefy/server/routes/set.py/choose_unit_route