def users_count(self):
        return self._user_ids.size
set parameters according to specification
dataset/ETHPy150Open muricoca/crab/scikits/crab/models/classes.py/MatrixBooleanPrefDataModel.users_count--crossover with--dataset/ETHPy150Open projectatomic/osbs-client/osbs/build/build_request.py/ProductionBuild.set_params