title: What does gym.make('CartPole-v0') return and how it does it work?
body: <p>I know <code>env=gym.make('CartPole-v0')</code> is of type <code>gym.wrappers.time_limit.TimeLimit</code></p>
  
  <p>And I also know env is an "instance" of the class cartpole.py. My question is how, by just giving the name 'CartPole-v0', I got the access to the cartpole.py class. Where is that process implemented? I was trying to look for it on the gym folder from the site-package folder but I couldn't find/understand where that process takes place. I'm not sure if my statements above are accurate, I'm asking this question to understand the process behind the execution of gym.make('CartPole-v0') and of any topic related to it in order to learn more about coding in general. My guess is that I am misunderstanding something</p>