# Buggy code
def __init__(self, *, win_id, mode_manager, private, parent=None):
    super().__init__(
        win_id=win_id, mode_manager=mode_manager, private=private, parent=parent
    )
    widget = webview.WebEngineView(tabdata=self.data, win_id=win_id, private=private)
    self.history = WebEngineHistory(self)
    self.scroller = WebEngineScroller(self, parent=self)
    self.caret = WebEngineCaret(mode_manager=mode_manager, tab=self, parent=self)
    self.zoom = WebEngineZoom(tab=self, parent=self)
    self.search = WebEngineSearch(parent=self)
    self.printing = WebEnginePrinting()
    self.elements = WebEngineElements(tab=self)
    self.action = WebEngineAction(tab=self)
    # We're assigning settings in _set_widget
    self.settings = webenginesettings.WebEngineSettings(settings=None)
    self._set_widget(widget)
    self._connect_signals()
    self.backend = usertypes.Backend.QtWebEngine
    self._init_js()
    self._child_event_filter = None
    self._saved_zoom = None
    self._reload_url = None


# Traceback (ValueError)
16:39:44 DEBUG    init       app:_init_modules:468 Initializing websettings...
16:39:45 ERROR    misc       crashsignal:exception_hook:216 Uncaught exception
Traceback (most recent call last):
File "/bin/qutebrowser", line 11, in <module>
load_entry_point('qutebrowser==1.1.1', 'gui_scripts', 'qutebrowser')()
File "/usr/lib/python3.6/site-packages/qutebrowser/qutebrowser.py", line 188, in main
return app.run(args)
File "/usr/lib/python3.6/site-packages/qutebrowser/app.py", line 137, in run
init(args, crash_handler)
File "/usr/lib/python3.6/site-packages/qutebrowser/app.py", line 163, in init
_init_modules(args, crash_handler)
File "/usr/lib/python3.6/site-packages/qutebrowser/app.py", line 469, in _init_modules
websettings.init(args)
File "/usr/lib/python3.6/site-packages/qutebrowser/config/websettings.py", line 215, in init
webenginesettings.init(args)
File "/usr/lib/python3.6/site-packages/qutebrowser/browser/webengine/webenginesettings.py", line 297, in init
websettings.init_mappings(MAPPINGS)
File "/usr/lib/python3.6/site-packages/qutebrowser/config/websettings.py", line 198, in init_mappings
mapping.set(value)
File "/usr/lib/python3.6/site-packages/qutebrowser/config/websettings.py", line 72, in set
self._set(value, settings=settings)
File "/usr/lib/python3.6/site-packages/qutebrowser/browser/webengine/webenginesettings.py", line 154, in _set
filenames = [self._find_installed(code) for code in value]
File "/usr/lib/python3.6/site-packages/qutebrowser/browser/webengine/webenginesettings.py", line 154, in <listcomp>
filenames = [self._find_installed(code) for code in value]
File "/usr/lib/python3.6/site-packages/qutebrowser/browser/webengine/webenginesettings.py", line 143, in _find_installed
local_filename = spell.local_filename(code)
File "/usr/lib/python3.6/site-packages/qutebrowser/browser/webengine/spell.py", line 64, in local_filename
all_installed = local_files(code)
File "/usr/lib/python3.6/site-packages/qutebrowser/browser/webengine/spell.py", line 51, in local_files
for matching_dict in sorted(matching_dicts, key=version, reverse=True):
File "/usr/lib/python3.6/site-packages/qutebrowser/browser/webengine/spell.py", line 36, in version
.format(filename))
ValueError: the given dictionary file name is malformed: /usr/share/qt/qtwebengine_dictionaries/en-US.bdic

# Fixed code
def __init__(self, *, win_id, mode_manager, private, parent=None):
    super().__init__(
        win_id=win_id, mode_manager=mode_manager, private=private, parent=parent
    )
    widget = webview.WebEngineView(tabdata=self.data, win_id=win_id, private=private)
    self.history = WebEngineHistory(self)
    self.scroller = WebEngineScroller(self, parent=self)
    self.caret = WebEngineCaret(mode_manager=mode_manager, tab=self, parent=self)
    self.zoom = WebEngineZoom(tab=self, parent=self)
    self.search = WebEngineSearch(parent=self)
    self.printing = WebEnginePrinting()
    self.elements = WebEngineElements(tab=self)
    self.action = WebEngineAction(tab=self)
    # We're assigning settings in _set_widget
    self.settings = webenginesettings.WebEngineSettings(settings=None)
    self._set_widget(widget)
    self._connect_signals()
    self.backend = usertypes.Backend.QtWebEngine
    self._child_event_filter = None
    self._saved_zoom = None
    self._reload_url = None
    config.instance.changed.connect(self._on_config_changed)
    self._init_js()