Update README.md

Update usage code

README.md

@@ -33,5 +33,26 @@ TODO: Add your code
 from stable_baselines3 import ...
 from huggingface_sb3 import load_from_hub
 
-...
+from stable_baselines3 import PPO
+from stable_baselines3.common.evaluation import evaluate_policy
+from stable_baselines3.common.env_util import make_vec_env
+
+repo_id = "kinkpunk/Lunar-Landing-Program" 
+filename = "LunarProgram-PPO.zip" 
+
+custom_objects = {
+            "learning_rate": 0.0,
+            "lr_schedule": lambda _: 0.0,
+            "clip_range": lambda _: 0.0,
+}
+
+checkpoint = load_from_hub(repo_id, filename)
+model = PPO.load(checkpoint, custom_objects=custom_objects, print_system_info=True)
+
+env = make_vec_env('LunarLander-v2', n_envs=1)
+
+# Evaluate the model
+mean_reward, std_reward = evaluate_policy(model, env, n_eval_episodes=10, deterministic=True)
+# Print the results
+print('mean_reward={:.2f} +/- {:.2f}'.format(mean_reward, std_reward))
 ```