def calc_gradient(self, inputs=None, outputs=None, mode='auto',
                      return_format='array', force_regen=False, options=None):

        return self._system.calc_gradient(inputs, outputs, mode=mode,
                                       options=options if options else self.parent.gradient_options,
                                       iterbase=self._iterbase(),
                                       return_format=return_format)
Get a hash value for this :class:`DBRef`.
dataset/ETHPy150Open OpenMDAO/OpenMDAO-Framework/openmdao.main/src/openmdao/main/workflow.py/Workflow.calc_gradient--crossover with--dataset/ETHPy150Open mongodb/mongo-python-driver/bson/dbref.py/DBRef.__hash__