diff --git a/src/app.py b/src/app.py
index 4dd61d4..7bcf103 100644
--- a/src/app.py
+++ b/src/app.py
@@ -97,7 +97,6 @@ def main() -> None:
         client.loop_forever()  # This blocks
     except KeyboardInterrupt:
         logging.info("SIGINT recieved! Stopping...")
-        pass
 
     client.disconnect()
     loopingtimer.stop()
diff --git a/src/preprocessor/soundpreprocessor.py b/src/preprocessor/soundpreprocessor.py
index 87949ee..a4324db 100644
--- a/src/preprocessor/soundpreprocessor.py
+++ b/src/preprocessor/soundpreprocessor.py
@@ -80,8 +80,9 @@ class SoundPreProcessor(AbcPreProcessor):
 
         logging.info("The loaded model contains the following classes: " + ", ".join(self._classes))
         if target_class_name not in self._classes:
-            raise Exception(
-                f"The specified target class {target_class_name} is not in the possible classes (Wrong model info?)")
+            raise ValueError(
+                f"The specified target class {target_class_name} is not in the possible classes (Wrong model info?)"
+            )
 
         self._target_id = self._classes.index(target_class_name)
 
@@ -97,10 +98,10 @@ class SoundPreProcessor(AbcPreProcessor):
         signal = audioBasicIO.stereo_to_mono(signal)
 
         if sampling_rate == 0:
-            raise Exception("Could not read the file properly: Sampling rate zero")
+            raise AssertionError("Could not read the file properly: Sampling rate zero")
 
         if signal.shape[0] / float(sampling_rate) <= self._mid_window:
-            raise Exception("Could not read the file properly: Signal shape is not good")
+            raise AssertionError("Could not read the file properly: Signal shape is not good")
 
         # feature extraction:
         mid_features, s, _ = \
diff --git a/src/utils/loopingtimer.py b/src/utils/loopingtimer.py
index 3f8add3..efaeef9 100644
--- a/src/utils/loopingtimer.py
+++ b/src/utils/loopingtimer.py
@@ -15,7 +15,7 @@ class LoopingTimer:
     """
     Looping timer. Executes a function and repeates it in the given interval.
     """
-    def __init__(self, interval, function, tick_args=[], tick_kwargs={}):
+    def __init__(self, interval, function, tick_args=None, tick_kwargs=None):
         """
         Initialize class
         :param interval:
@@ -26,8 +26,8 @@ class LoopingTimer:
         self._timer = None
         self.interval = interval
         self.function = function
-        self._tick_args = tick_args
-        self._tick_kwargs = tick_kwargs
+        self._tick_args = tick_args or []
+        self._tick_kwargs = tick_kwargs or {}
         self.is_running = False
         self.start()