AttributeError: 'Config' object has no attribute 'num_envs'

~/anaconda3/envs/ai4finance/lib/python3.8/site-packages/elegantrl/agents/AgentSAC.py in __init__(self, net_dims, state_dim, action_dim, gpu_id, args)
15 self.act_class = getattr(self, 'act_class', ActorSAC)
16 self.cri_class = getattr(self, 'cri_class', CriticTwin)
---> 17 super().__init__(net_dims=net_dims, state_dim=state_dim, action_dim=action_dim, gpu_id=gpu_id, args=args)
18 self.cri_target = deepcopy(self.cri)
19

~/anaconda3/envs/ai4finance/lib/python3.8/site-packages/elegantrl/agents/AgentBase.py in __init__(self, net_dims, state_dim, action_dim, gpu_id, args)
21 def __init__(self, net_dims: [int], state_dim: int, action_dim: int, gpu_id: int = 0, args: Config = Config()):
22 self.gamma = args.gamma # discount factor of future rewards
---> 23 self.num_envs = args.num_envs # the number of sub envs in vectorized env. `num_envs=1` in single env.
24 self.batch_size = args.batch_size # num of transitions sampled from replay buffer.
25 self.repeat_times = args.repeat_times # repeatedly update network using ReplayBuffer

AttributeError: 'Config' object has no attribute 'num_envs'