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

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Author: pre-commit-ci[bot]

tests/tests_pytorch/callbacks/test_model_checkpoint_additional_cases.py

@@ -1,7 +1,7 @@
 import math
+import os
 from datetime import timedelta
 
-import os
 import pytest
 import torch
 import torch.nn as nn