def _getter(self, attr, fallback=None):
        return self.reader[attr][0] if attr in self.reader else fallback
populates variable into a context
dataset/ETHPy150Open tooxie/shiva-server/shiva/utils.py/MetadataManager._getter--crossover with--dataset/ETHPy150Open adlibre/Adlibre-DMS/adlibre_dms/apps/mdtui/templatetags/index_keys.py/set_field_value