use helper function to extract archive in CelebA (#4557)

Co-authored-by: Prabhat Roy <prabhatroy@fb.com>

torchvision/datasets/celeba.py

@@ -6,7 +6,7 @@ from typing import Any, Callable, List, Optional, Union, Tuple
 import PIL
 import torch
 
-from .utils import download_file_from_google_drive, check_integrity, verify_str_arg
+from .utils import download_file_from_google_drive, check_integrity, verify_str_arg, extract_archive
 from .vision import VisionDataset
 
 CSV = namedtuple("CSV", ["header", "index", "data"])
@@ -142,8 +142,6 @@ class CelebA(VisionDataset):
         return os.path.isdir(os.path.join(self.root, self.base_folder, "img_align_celeba"))
 
     def download(self) -> None:
-        import zipfile
-
         if self._check_integrity():
             print("Files already downloaded and verified")
             return
@@ -151,8 +149,7 @@ class CelebA(VisionDataset):
         for (file_id, md5, filename) in self.file_list:
             download_file_from_google_drive(file_id, os.path.join(self.root, self.base_folder), filename, md5)
 
-        with zipfile.ZipFile(os.path.join(self.root, self.base_folder, "img_align_celeba.zip"), "r") as f:
-            f.extractall(os.path.join(self.root, self.base_folder))
+        extract_archive(os.path.join(self.root, self.base_folder, "img_align_celeba.zip"))
 
     def __getitem__(self, index: int) -> Tuple[Any, Any]:
         X = PIL.Image.open(os.path.join(self.root, self.base_folder, "img_align_celeba", self.filename[index]))