def checkpoint_attributes(self):
        ''' Return the attributes needed to restore the model from a checkpoint
        '''
        return {
            'qnet': self.qnet.state_dict(),
            'optimizer': self.optimizer.state_dict(),
            'num_actions': self.num_actions,
            'learning_rate': self.learning_rate,
            'state_shape': self.state_shape,
            'mlp_layers': self.mlp_layers,
            'device': self.device
        }
 Return the attributes needed to restore the model from a checkpoint
        
rlcard/agents/dqn_agent.py