# Buggy code
def init():
    """Initialize QtWebEngine-specific modules."""
    # For some reason we need to keep a reference, otherwise the scheme handler
    # won't work...
    # https://www.riverbankcomputing.com/pipermail/pyqt/2016-September/038075.html
    global _qute_scheme_handler

    app = QApplication.instance()
    log.init.debug("Initializing qute://* handler...")
    _qute_scheme_handler = webenginequtescheme.QuteSchemeHandler(parent=app)
    _qute_scheme_handler.install(webenginesettings.default_profile)
    _qute_scheme_handler.install(webenginesettings.private_profile)

    log.init.debug("Initializing request interceptor...")
    host_blocker = objreg.get("host-blocker")
    req_interceptor = interceptor.RequestInterceptor(host_blocker, parent=app)
    req_interceptor.install(webenginesettings.default_profile)
    req_interceptor.install(webenginesettings.private_profile)

    log.init.debug("Initializing QtWebEngine downloads...")
    download_manager = webenginedownloads.DownloadManager(parent=app)
    download_manager.install(webenginesettings.default_profile)
    download_manager.install(webenginesettings.private_profile)
    objreg.register("webengine-download-manager", download_manager)

    greasemonkey = objreg.get("greasemonkey")
    greasemonkey.scripts_reloaded.connect(webenginesettings.inject_userscripts)
    webenginesettings.inject_userscripts()


# 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():
    """Initialize QtWebEngine-specific modules."""
    # For some reason we need to keep a reference, otherwise the scheme handler
    # won't work...
    # https://www.riverbankcomputing.com/pipermail/pyqt/2016-September/038075.html
    global _qute_scheme_handler

    app = QApplication.instance()
    log.init.debug("Initializing qute://* handler...")
    _qute_scheme_handler = webenginequtescheme.QuteSchemeHandler(parent=app)
    _qute_scheme_handler.install(webenginesettings.default_profile)
    _qute_scheme_handler.install(webenginesettings.private_profile)

    log.init.debug("Initializing request interceptor...")
    host_blocker = objreg.get("host-blocker")
    req_interceptor = interceptor.RequestInterceptor(host_blocker, parent=app)
    req_interceptor.install(webenginesettings.default_profile)
    req_interceptor.install(webenginesettings.private_profile)

    log.init.debug("Initializing QtWebEngine downloads...")
    download_manager = webenginedownloads.DownloadManager(parent=app)
    download_manager.install(webenginesettings.default_profile)
    download_manager.install(webenginesettings.private_profile)
    objreg.register("webengine-download-manager", download_manager)