Fix copypaste collate pickle issues (#6181)

references/detection/train.py

@@ -35,6 +35,11 @@ from torchvision.transforms import InterpolationMode
 from transforms import SimpleCopyPaste
 
 
+def copypaste_collate_fn(batch):
+    copypaste = SimpleCopyPaste(blending=True, resize_interpolation=InterpolationMode.BILINEAR)
+    return copypaste(*utils.collate_fn(batch))
+
+
 def get_dataset(name, image_set, transform, data_path):
     paths = {"coco": (data_path, get_coco, 91), "coco_kp": (data_path, get_coco_kp, 2)}
     p, ds_fn, num_classes = paths[name]
@@ -194,11 +199,6 @@ def main(args):
         if args.data_augmentation != "lsj":
             raise RuntimeError("SimpleCopyPaste algorithm currently only supports the 'lsj' data augmentation policies")
 
-        copypaste = SimpleCopyPaste(resize_interpolation=InterpolationMode.BILINEAR, blending=True)
-
-        def copypaste_collate_fn(batch):
-            return copypaste(*utils.collate_fn(batch))
-
         train_collate_fn = copypaste_collate_fn
 
     data_loader = torch.utils.data.DataLoader(