def sample(self):
        ''' Sample a minibatch from the replay memory

        Returns:
            state_batch (list): a batch of states
            action_batch (list): a batch of actions
            reward_batch (list): a batch of rewards
            next_state_batch (list): a batch of states
            done_batch (list): a batch of dones
        '''
        samples = random.sample(self.memory, self.batch_size)
        samples = tuple(zip(*samples))
        return tuple(map(np.array, samples[:-1])) + (samples[-1],)
 Sample a minibatch from the replay memory

        Returns:
            state_batch (list): a batch of states
            action_batch (list): a batch of actions
            reward_batch (list): a batch of rewards
            next_state_batch (list): a batch of states
            done_batch (list): a batch of dones
        
rlcard/agents/dqn_agent.py