diff --git a/amodem/__main__.py b/amodem/__main__.py
index 9bbd8de..2243c4b 100644
--- a/amodem/__main__.py
+++ b/amodem/__main__.py
@@ -88,11 +88,11 @@ def FileType(mode, interface_factory=None):
 
 
 def get_volume_cmd(args):
-    volume_controllers = [
-        dict(test='pactl --version',
-             send='pactl set-sink-volume @DEFAULT_SINK@',
-             recv='pactl set-source-volume @DEFAULT_SOURCE@')
-    ]
+    volume_controllers = [{
+        'test': 'pactl --version',
+        'send': 'pactl set-sink-volume @DEFAULT_SINK@',
+        'recv': 'pactl set-source-volume @DEFAULT_SOURCE@'
+    }]
     if args.calibrate == 'auto':
         for c in volume_controllers:
             if os.system(c['test']) == 0:
diff --git a/amodem/audio.py b/amodem/audio.py
index 3b70ff8..811b5fc 100644
--- a/amodem/audio.py
+++ b/amodem/audio.py
@@ -7,6 +7,10 @@ import time
 log = logging.getLogger(__name__)
 
 
+class AudioError(Exception):
+    pass
+
+
 class Interface:
     def __init__(self, config, debug=False):
         self.debug = bool(debug)
@@ -35,7 +39,7 @@ class Interface:
 
     def _error_check(self, res):
         if res != 0:
-            raise Exception(res, self._error_string(res))
+            raise AudioError(res, self._error_string(res))
 
     def __enter__(self):
         self.call('Initialize')
diff --git a/amodem/calib.py b/amodem/calib.py
index 59f7f45..be9fee7 100644
--- a/amodem/calib.py
+++ b/amodem/calib.py
@@ -75,10 +75,10 @@ def detector(config, src, frame_length=200):
         else:
             msg = f'too {errors[flags.index(False)]} signal'
 
-        yield dict(
-            freq=freq, rms=rms, peak=peak, coherency=coherency,
-            total=total, success=success, msg=msg
-        )
+        yield {
+            'freq': freq, 'rms': rms, 'peak': peak, 'coherency': coherency,
+            'total': total, 'success': success, 'msg': msg
+        }
 
 
 def volume_calibration(result_iterator, volume_ctl):
diff --git a/amodem/dsp.py b/amodem/dsp.py
index c0afd45..68f77b2 100644
--- a/amodem/dsp.py
+++ b/amodem/dsp.py
@@ -79,7 +79,7 @@ class MODEM:
         symbols = np.array(list(symbols))
         bits_per_symbol = np.log2(len(symbols))
         bits_per_symbol = np.round(bits_per_symbol)
-        N = (2 ** bits_per_symbol)
+        N = 2 ** bits_per_symbol
         assert N == len(symbols)
         bits_per_symbol = int(bits_per_symbol)
 
diff --git a/amodem/recv.py b/amodem/recv.py
index 0ccc272..ff8a3e6 100644
--- a/amodem/recv.py
+++ b/amodem/recv.py
@@ -43,7 +43,7 @@ class Receiver:
         self.plt.subplot(1, 2, 2)
         self.plt.plot(np.abs(S))
         self.plt.plot(equalizer.prefix)
-        errors = (bits != equalizer.prefix)
+        errors = bits != equalizer.prefix
         if any(errors):
             msg = f'Incorrect prefix: {sum(errors)} errors'
             raise ValueError(msg)
diff --git a/amodem/stream.py b/amodem/stream.py
index e542dbe..8b4a60f 100644
--- a/amodem/stream.py
+++ b/amodem/stream.py
@@ -5,7 +5,7 @@ class Reader:
 
     wait = 0.2
     timeout = 2.0
-    bufsize = (8 << 10)
+    bufsize = 8 << 10
 
     def __init__(self, fd, data_type=None, eof=False):
         self.fd = fd