diff --git a/torchrl/envs/libs/pettingzoo.py b/torchrl/envs/libs/pettingzoo.py
index 0d8d2ffe687..812ccdb07fa 100644
--- a/torchrl/envs/libs/pettingzoo.py
+++ b/torchrl/envs/libs/pettingzoo.py
@@ -157,7 +157,7 @@ class PettingZooWrapper(_EnvWrapper):
             them to categorical or one-hot.
         seed (int, optional): the seed. Defaults to ``None``.
         done_on_any (bool, optional): whether the environment's done keys are set by aggregating the agent keys
-            using ``any()`` (when True) or ``all()`` (when False). Default (``None``) is to use ``any()`` for
+            using ``any()`` (when ``True``) or ``all()`` (when ``False``). Default (``None``) is to use ``any()`` for
             parallel environments and ``all()`` for AEC ones.
 
     Examples: