def save_last_sync(self, ids, process):
        try:
            spec = {'_id': 'last_sync'}
            document = {'$set': {process: ids}}
            self.db.internal.update(spec, document, upsert=True)
        except Exception as e:
            raise DatabaseException(e)
def forward(self, x):
        mean_x = self.mean_module(x)
        covar_x = self.covar_module(x)
        return MultivariateNormal(mean_x, covar_x)