# Buggy code
def _buffer(skip_win_id=None):
    """Helper to get the completion model for buffer/other_buffer.

    Args:
        skip_win_id: The id of the window to skip, or None to include all.
    """

    def delete_buffer(data):
        """Close the selected tab."""
        win_id, tab_index = data[0].split("/")
        tabbed_browser = objreg.get(
            "tabbed-browser", scope="window", window=int(win_id)
        )
        tabbed_browser.on_tab_close_requested(int(tab_index) - 1)

    model = completionmodel.CompletionModel(column_widths=(6, 40, 54))

    for win_id in objreg.window_registry:
        if skip_win_id and win_id == skip_win_id:
            continue
        tabbed_browser = objreg.get("tabbed-browser", scope="window", window=win_id)
        if tabbed_browser.shutting_down:
            continue
        tabs = []
        for idx in range(tabbed_browser.count()):
            tab = tabbed_browser.widget(idx)
            tabs.append(
                (
                    "{}/{}".format(win_id, idx + 1),
                    tab.url().toDisplayString(),
                    tabbed_browser.page_title(idx),
                )
            )
        cat = listcategory.ListCategory(
            "{}".format(win_id), tabs, delete_func=delete_buffer
        )
        model.add_category(cat)

    return model


# 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 _buffer(skip_win_id=None):
    """Helper to get the completion model for buffer/other_buffer.

    Args:
        skip_win_id: The id of the window to skip, or None to include all.
    """

    def delete_buffer(data):
        """Close the selected tab."""
        win_id, tab_index = data[0].split("/")
        tabbed_browser = objreg.get(
            "tabbed-browser", scope="window", window=int(win_id)
        )
        tabbed_browser.on_tab_close_requested(int(tab_index) - 1)

    model = completionmodel.CompletionModel(column_widths=(6, 40, 54))

    for win_id in objreg.window_registry:
        if skip_win_id is not None and win_id == skip_win_id:
            continue
        tabbed_browser = objreg.get("tabbed-browser", scope="window", window=win_id)
        if tabbed_browser.shutting_down:
            continue
        tabs = []
        for idx in range(tabbed_browser.widget.count()):
            tab = tabbed_browser.widget.widget(idx)
            tabs.append(
                (
                    "{}/{}".format(win_id, idx + 1),
                    tab.url().toDisplayString(),
                    tabbed_browser.widget.page_title(idx),
                )
            )
        cat = listcategory.ListCategory(
            "{}".format(win_id), tabs, delete_func=delete_buffer
        )
        model.add_category(cat)

    return model