Apply suggestions from code review

Co-authored-by: mikaylagawarecki <mikaylagawarecki@gmail.com>

Author: Vincent Moens

torchrl/envs/custom/llm.py

@@ -31,7 +31,7 @@ class LLMEnv(EnvBase):
     integers representing a sequence of tokens.
     The action is also a string or a tensor of integers, which is concatenated to the previous observation to form the
     new observation.
-
+     Prompts to the language model can be loaded when the environment is ``reset`` if the environment is created via :meth:`~from_dataloader`
     Args:
         observation_key (NestedKey, optional): The key in the tensordict where the observation is stored. Defaults to
             ``"observation"``.
@@ -138,7 +138,7 @@ def from_dataloader(
     ) -> LLMEnv:
         """Creates an LLMEnv instance from a dataloader.
 
-        This method creates an LLMEnv instance and appends a DataLoadingPrimer to it, which loads data from the provided dataloader.
+        This method creates an LLMEnv instance and appends a DataLoadingPrimer to it, which populates ``data_keys`` (by default ``observation_key``) with data from the provided dataloader when the environment is reset.
 
         Args:
             dataloader (DataLoader): The dataloader to load data from.
@@ -151,7 +151,7 @@ def from_dataloader(
                 unbounded vocabulary. Defaults to ``None``.
             primers (Composite | None, optional): The primers to use for each key in the dataloader.
                 Defaults to ``None``.
-            data_keys (list[NestedKey] | None, optional): The keys to use for each item in the dataloader.
+            data_keys (list[NestedKey] | None, optional): The keys to use for each item in the dataloader. If not passed ``observation_key`` will be populated with the data.
                 Defaults to ``None``.
             data_specs (list[TensorSpec] | None, optional): The specs to use for each item in the dataloader.
                 Defaults to ``None``.

torchrl/envs/transforms/rlhf.py

@@ -82,15 +82,15 @@ def pad_tensor(tensor):
 
 
 class DataLoadingPrimer(TensorDictPrimer):
-    """A primer that loads data from a dataloader and stacks it into a tensordict.
+    """A primer that loads data from a dataloader and converts it into a tensordict using ``stack_method``.
 
     Args:
         dataloader (Iterable[Any]): The dataloader to load data from.
         primers (Composite | None, optional): The primers to use for each key in the dataloader. Defaults to None.
         data_keys (List[NestedKey] | None, optional): The keys to use for each item in the dataloader. Defaults to None.
         data_specs (List[TensorSpec] | None, optional): The specs to use for each item in the dataloader. Defaults to None.
         example_data (Any, optional): Example data to use for initializing the primer. Defaults to None.
-        stack_method (Callable[[Any], Any] | Literal["as_nested_tensor", "as_padded_tensor"], optional): The method to use for stacking the data. Defaults to None.
+        stack_method (Callable[[Any], Any] | Literal["as_nested_tensor", "as_padded_tensor"], optional): The method to use for stacking the data. Defaults to ``maybe_dense_stack``.
 
     Attributes:
         dataloader (Iterable[Any]): The dataloader to load data from.