def __init__(self, *args, **kwargs):
        self.cls = self.model_class

        assert hasattr(self, 'session'), "session is expected"
        assert self.session is not None, "session must be initialized" \
                                         "by the derived class"
Sets the valdidator.
dataset/ETHPy150Open dealertrack/djangorest-alchemy/djangorest_alchemy/managers.py/AlchemyModelManager.__init__--crossover with--dataset/ETHPy150Open sdispater/cleo/cleo/inputs/input_argument.py/InputArgument.set_validator