Final answer:
The issue of 'gym envs Box2D has no attribute lunarlander' typically indicates that the LunarLander environment is not installed or misconfigured. To resolve this, install Box2D and confirm its proper integration with the gym library. Make sure to call the environment correctly in your code as 'LunarLander-v2'.
Step-by-step explanation:
If you encounter an error saying that the gym environments, specifically Box2D, has no attribute 'lunarlander', it usually means that the LunarLander environment is not installed or properly configured in your OpenAI Gym setup. The OpenAI Gym Box2D environments, including LunarLander, sometimes require additional dependencies that are not included in the basic gym installation.
To solve this issue, you should ensure that you have installed Box2D along with the gym library. This can often be done via pip with commands such as 'pip install Box2D' or 'pip install gym[box2d]' which installs the Box2D environments alongside the standard gym set. Once you've confirmed the installation, you should be able to import and use the LunarLander environment without encountering the attribute error.
If issues persist after installation, it might be necessary to ensure your PATH variables are set correctly or that you are using a virtual environment where the dependencies are properly installed. It is also possible that your specific code is requesting 'lunarlander' incorrectly; it should be 'LunarLander-v2' when used in gym.make() function.