Explain the concept of 'experience replay' and its purpose in Deep Q-Networks (DQNs).

Experience replay is a technique used in Deep Q-Networks (DQNs) to improve the stability and efficiency of the learning process. In standard Q-learning, the agent learns directly from its experiences as they occur, updating the Q-values after each step. However, this can lead to unstable learning because consecutive experiences are often highly correlated, and small changes in the Q-values can have a significant impact on the policy. Experience replay addresses this issue by storing the agent's experiences in a replay buffer, which is a....