[pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

Author: pre-commit-ci[bot]

src/lightning/pytorch/plugins/io/async_plugin.py

@@ -13,7 +13,7 @@
 # limitations under the License.
 
 from concurrent.futures import ThreadPoolExecutor
-from typing import Any, Optional, TYPE_CHECKING
+from typing import TYPE_CHECKING, Any, Optional
 
 import torch
 from lightning_utilities.core.apply_func import apply_to_collection
@@ -78,7 +78,7 @@ def _save_checkpoint(*args: Any, **kwargs: Any) -> None:
     def teardown(self) -> None:
         """This method is called to close the threads."""
         if self._executor is None:
-            return None
+            return
         self._executor.shutdown(wait=True)
         self._executor = None
 
@@ -90,4 +90,4 @@ def teardown(self) -> None:
 # snapshot the checkpoint payload on the caller thread to avoid races with parameter mutation
 def _clone_tensor(t: torch.Tensor) -> torch.Tensor:
     # detach to avoid autograd history and clone to take a point-in-time copy
-    return t.detach().clone()
+    return t.detach().clone()