diff --git a/src/settings.py b/src/settings.py
index 0bd2ec1..ac3aa2a 100644
--- a/src/settings.py
+++ b/src/settings.py
@@ -38,7 +38,4 @@ class Settings:
         """Return the corresponding setting.
 
         Return None if there is no such setting yet."""
-        try:
-            return self._dct[attr]
-        except Exception:
-            return None
+        return self._dct.get(attr, None)
diff --git a/src/utilities.py b/src/utilities.py
index 6565f11..dd08758 100644
--- a/src/utilities.py
+++ b/src/utilities.py
@@ -30,12 +30,12 @@ class UniqueMessageBox(QMessageBox):
         """Overrides QMessageBox.exec. Call the parent method if there are no
         other instances executing exec; also set the current font.
         Otherwise return None,"""
-        if UniqueMessageBox._open_message:
+        if self.__class__._open_message:
             return None
         self.setFont(self._font)
-        UniqueMessageBox._open_message = True
+        self.__class__._open_message = True
         answer = super().exec()
-        UniqueMessageBox._open_message = False
+        self.__class__._open_message = False
         return answer
 
     def show(self):
diff --git a/src/versioncontroller.py b/src/versioncontroller.py
index cfe9a2c..5712083 100644
--- a/src/versioncontroller.py
+++ b/src/versioncontroller.py
@@ -63,14 +63,9 @@ def _download_versions_file():
         }
     }
     """
-    try:
-        version_dict = json.load(
-            BytesIO(download_file(Constants.VERSION_LINK))
-        )[get_os()]
-    except Exception:
-        return None
-    else:
-        return version_dict
+    return json.load(
+        BytesIO(download_file(Constants.VERSION_LINK))
+    ).get(get_os(), None)
 
 
 class VersionController:
@@ -80,7 +75,6 @@ class VersionController:
 
     def __init__(self, dct=None):
         """Initialize the dictionary"""
-        super().__init__()
         self._dct = dct
 
     def __getattr__(self, attr):
@@ -89,16 +83,14 @@ class VersionController:
         if self._dct is None:
             if not self.update():
                 return None
-        try:
-            dct_element = self._dct[attr]
-        except Exception("ERROR: Invalid attribute!"):
+        dct_element = self._dct.get(attr, None)
+        if dct_element is None:
             return None
+        if isinstance(dct_element, dict):
+            setattr(self, attr, type(self)(dct_element))
         else:
-            if isinstance(dct_element, dict):
-                setattr(self, attr, type(self)(dct_element))
-            else:
-                setattr(self, attr, dct_element)
-            return getattr(self, attr)
+            setattr(self, attr, dct_element)
+        return getattr(self, attr)
 
     def update(self):
         """Reset the dictionary to the correspondig json file containing
diff --git a/src/web_utilities.py b/src/web_utilities.py
index 2efa362..70bd702 100644
--- a/src/web_utilities.py
+++ b/src/web_utilities.py
@@ -37,10 +37,9 @@ def _download_multiline_file_as_list(url=Database.LINK_REF):
     The downloaded file is a csv file with columns (last version == last line):
     data.zip_SHA256 | db.csv_SHA256 | Version | Creation_date"""
     try:
-        f = download_file(url, encoding="UTF-8").splitlines()[-1].split(Database.DELIMITER)
+        return download_file(url, encoding="UTF-8").splitlines()[-1].split(Database.DELIMITER)
     except Exception:
         return None
-    return f
 
 
 def get_folder_hash_code():