Optimize imports (#9464)

* Optimize imports

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

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* Reformat

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

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

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

segment/train.py

@@ -39,8 +39,6 @@ if str(ROOT) not in sys.path:
     sys.path.append(str(ROOT))  # add ROOT to PATH
 ROOT = Path(os.path.relpath(ROOT, Path.cwd()))  # relative
 
-import torch.nn.functional as F
-
 import segment.val as validate  # for end-of-epoch mAP
 from models.experimental import attempt_load
 from models.yolo import SegmentationModel