# Buggy code
def _save_all(self, *, only_window=None, with_private=False):
    """Get a dict with data for all windows/tabs."""
    data = {"windows": []}
    if only_window is not None:
        winlist = [only_window]
    else:
        winlist = objreg.window_registry

    for win_id in sorted(winlist):
        tabbed_browser = objreg.get("tabbed-browser", scope="window", window=win_id)
        main_window = objreg.get("main-window", scope="window", window=win_id)

        # We could be in the middle of destroying a window here
        if sip.isdeleted(main_window):
            continue

        if tabbed_browser.private and not with_private:
            continue

        win_data = {}
        active_window = QApplication.instance().activeWindow()
        if getattr(active_window, "win_id", None) == win_id:
            win_data["active"] = True
        win_data["geometry"] = bytes(main_window.saveGeometry())
        win_data["tabs"] = []
        if tabbed_browser.private:
            win_data["private"] = True
        for i, tab in enumerate(tabbed_browser.widgets()):
            active = i == tabbed_browser.currentIndex()
            win_data["tabs"].append(self._save_tab(tab, active))
        data["windows"].append(win_data)
    return data


# 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 _save_all(self, *, only_window=None, with_private=False):
    """Get a dict with data for all windows/tabs."""
    data = {"windows": []}
    if only_window is not None:
        winlist = [only_window]
    else:
        winlist = objreg.window_registry

    for win_id in sorted(winlist):
        tabbed_browser = objreg.get("tabbed-browser", scope="window", window=win_id)
        main_window = objreg.get("main-window", scope="window", window=win_id)

        # We could be in the middle of destroying a window here
        if sip.isdeleted(main_window):
            continue

        if tabbed_browser.private and not with_private:
            continue

        win_data = {}
        active_window = QApplication.instance().activeWindow()
        if getattr(active_window, "win_id", None) == win_id:
            win_data["active"] = True
        win_data["geometry"] = bytes(main_window.saveGeometry())
        win_data["tabs"] = []
        if tabbed_browser.private:
            win_data["private"] = True
        for i, tab in enumerate(tabbed_browser.widgets()):
            active = i == tabbed_browser.widget.currentIndex()
            win_data["tabs"].append(self._save_tab(tab, active))
        data["windows"].append(win_data)
    return data