Fix flake8

tests/datasets/test_utils.py

@@ -1,4 +1,4 @@
-from typing import Tuple, Union
+from typing import Tuple
 from pathlib import Path
 
 import pytest

torchgeo/datasets/utils.py

@@ -1,6 +1,6 @@
 import contextlib
 import os
-from typing import Dict, Iterator, List, Tuple, Union
+from typing import Dict, Iterator, List, Tuple
 
 import torch
 from torch import Tensor