Do the V5 environments perform frame pooling?

The README says the V5 environments follow Machado et al. 2018, who use max-pooling over the last two frames. I couldn't find any code or config option of this in the repository, so I'm wondering do the V5 environments automatically perform frame pooling?

Start with the README's description of the V5 environments and trace the V5 environment implementation for any frame-processing or pooling logic and configuration. Compare the observed behavior with Machado et al. 2018; done means documenting whether pooling is automatic and, if it is absent, identifying the required change.

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