Fix flake8 errors

hifiscan/audio.py

@@ -85,5 +85,3 @@ class PlayItem:
         chunk = self.sound[self.index:idx]
         self.index = idx
         return chunk
-
-

hifiscan/io_.py

@@ -23,7 +23,7 @@ def write_wav(path: str, data: np.ndarray, rate: int, width: int = 4):
       rate: Sample rate in Hz.
       width: Sample width in bytes.
     """
-    if not width in [1, 2, 3, 4]:
+    if width not in [1, 2, 3, 4]:
         raise ValueError(f'Invalid sample width: {width}')
     data = np.asarray(data)
     ch = 1 if len(data.shape) < 2 else len(data)
@@ -58,20 +58,22 @@ def read_wav(path: str) -> Sound:
         frames = wav.readframes(n)
     if width == 4:
         buff = np.frombuffer(frames, np.int32)
-        data = buff.astype('f') / np.float32(2 ** 31 - 1)
+        norm = 2 ** 31 - 1
     elif width == 3:
         buff = np.frombuffer(frames, np.uint8)
         uints = buff[0::3].astype(np.uint32) << 8 \
             | buff[1::3].astype(np.uint32) << 16 \
             | buff[2::3].astype(np.uint32) << 24
-        data = uints.view(np.int32).astype('f') / np.float32(
-            2 ** 31 - 2 ** 8)
+        buff = uints.view(np.int32)
+        norm = 2 ** 31 - 2 ** 8
     elif width == 2:
         buff = np.frombuffer(frames, np.int16)
-        data = buff.astype('f') / np.float32(2 ** 15 - 1)
+        norm = 2 ** 15 - 1
     else:
         buff = np.frombuffer(frames, np.int8)
-        data = buff.astype('f') / np.float32(2 ** 7 - 1)
+        norm = 2 ** 7 - 1
+    data = buff.astype('f')
+    data /= np.float32(norm)
     data = data.reshape((-1, ch)).T
     return Sound(data, rate, width)