Improve Flake Rules (#1214)

torchaudio/sox_effects/sox_effects.py

 import os
-from pathlib import Path
 from typing import List, Tuple, Optional
 
 import torch

torchaudio/transforms.py

@@ -2,7 +2,6 @@
 
 import math
 from typing import Callable, Optional
-from warnings import warn
 
 import torch
 from torch import Tensor