Try to fix mypy issue with calculate_md5 (#6493)

torchvision/datasets/utils.py

@@ -65,7 +65,10 @@ def calculate_md5(fpath: str, chunk_size: int = 1024 * 1024) -> str:
     # Setting the `usedforsecurity` flag does not change anything about the functionality, but indicates that we are
     # not using the MD5 checksum for cryptography. This enables its usage in restricted environments like FIPS. Without
     # it torchvision.datasets is unusable in these environments since we perform a MD5 check everywhere.
-    md5 = hashlib.md5(**dict(usedforsecurity=False) if sys.version_info >= (3, 9) else dict())
+    if sys.version_info >= (3, 9):
+        md5 = hashlib.md5(usedforsecurity=False)
+    else:
+        md5 = hashlib.md5()
     with open(fpath, "rb") as f:
         for chunk in iter(lambda: f.read(chunk_size), b""):
             md5.update(chunk)