diff --git a/npbackup/gui/main.py b/npbackup/gui/main.py
index 1561cd7..c1664b0 100644
--- a/npbackup/gui/main.py
+++ b/npbackup/gui/main.py
@@ -597,7 +597,7 @@ def main_gui(config_dict: dict, config_file: str, version_string: str):
         if event == "configure":
             config_dict = config_gui(config_dict, config_file)
             # Make sure we trigger a GUI refresh when configuration is changed
-            event = 'state-button'
+            event = "state-button"
         if event == _t("generic.destination"):
             try:
                 if backend_type:
diff --git a/npbackup/gui/minimize_window.py b/npbackup/gui/minimize_window.py
index 2cdf7e9..6b273da 100644
--- a/npbackup/gui/minimize_window.py
+++ b/npbackup/gui/minimize_window.py
@@ -20,9 +20,9 @@ def minimize_current_window():
     """
     Minimizes current commandline window in GUI mode
     """
-    if os.name == 'nt':
+    if os.name == "nt":
         current_executable = os.path.abspath(sys.argv[0])
         # console window will have the name of current executable
         hwndMain = win32gui.FindWindow(None, current_executable)
         if hwndMain:
-            win32gui.ShowWindow(hwndMain, win32con.SW_MINIMIZE)
\ No newline at end of file
+            win32gui.ShowWindow(hwndMain, win32con.SW_MINIMIZE)