style(nyz): polish env manager/wrapper comments

ding/envs/env/default_wrapper.py

@@ -6,7 +6,21 @@
 
 
 def get_default_wrappers(env_wrapper_name: str, env_id: Optional[str] = None, caller: str = 'collector') -> List[dict]:
-    assert caller == 'collector' or 'evaluator'
+    """
+    Overview:
+        Get default wrappers for different environments used in ``DingEnvWrapper``.
+    Arguments:
+        - env_wrapper_name (:obj:`str`): The name of the environment wrapper.
+        - env_id (:obj:`Optional[str]`): The id of the specific environment, such as ``PongNoFrameskip-v4``.
+        - caller (:obj:`str`): The caller of the environment, including ``collector`` or ``evaluator``. Different \
+            caller may need different wrappers.
+    Returns:
+        - wrapper_list (:obj:`List[dict]`): The list of wrappers, each element is a config of the concrete wrapper.
+    Raises:
+        - NotImplementedError: ``env_wrapper_name`` is not in ``['mujoco_default', 'atari_default', \
+            'gym_hybrid_default', 'default']``
+    """
+    assert caller == 'collector' or 'evaluator', caller
     if env_wrapper_name == 'mujoco_default':
         return [
             EasyDict(type='delay_reward', kwargs=dict(delay_reward_step=3)),
@@ -35,4 +49,4 @@ def get_default_wrappers(env_wrapper_name: str, env_id: Optional[str] = None, ca
     elif env_wrapper_name == 'default':
         return [copy.deepcopy(eval_episode_return_wrapper)]
     else:
-        raise NotImplementedError()
+        raise NotImplementedError("not supported env_wrapper_name: {}".format(env_wrapper_name))

ding/envs/env_manager/__init__.py

@@ -1,5 +1,5 @@
 from .base_env_manager import BaseEnvManager, BaseEnvManagerV2, create_env_manager, get_env_manager_cls
 from .subprocess_env_manager import AsyncSubprocessEnvManager, SyncSubprocessEnvManager, SubprocessEnvManagerV2
 from .gym_vector_env_manager import GymVectorEnvManager
-# Do not import PoolEnvManager, because it depends on installation of `envpool`
+# Do not import PoolEnvManager here, because it depends on installation of `envpool`
 from .env_supervisor import EnvSupervisor