How do I get an agent's position in the environment in the `postprocess_trajectory` method?

[bbrighttaer]

I have a MARL problem where I need the physical position of the agent in the environment. For instance, in a 2D environment, I expect some tuple of 2 elements (x,y). I need to use this information in the postprocess_trajectory method of the Policy class. How can I achieve this? Many thanks for considering my request.