# Buggy code
def close_tab(self, tab, *, add_undo=True, new_undo=True):
    """Close a tab.

    Args:
        tab: The QWebView to be closed.
        add_undo: Whether the tab close can be undone.
        new_undo: Whether the undo entry should be a new item in the stack.
    """
    last_close = config.val.tabs.last_close
    count = self.count()

    if last_close == "ignore" and count == 1:
        return

    self._remove_tab(tab, add_undo=add_undo, new_undo=new_undo)

    if count == 1:  # We just closed the last tab above.
        if last_close == "close":
            self.close_window.emit()
        elif last_close == "blank":
            self.openurl(QUrl("about:blank"), newtab=True)
        elif last_close == "startpage":
            for url in config.val.url.start_pages:
                self.openurl(url, newtab=True)
        elif last_close == "default-page":
            self.openurl(config.val.url.default_page, newtab=True)


# 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 close_tab(self, tab, *, add_undo=True, new_undo=True):
    """Close a tab.

    Args:
        tab: The QWebView to be closed.
        add_undo: Whether the tab close can be undone.
        new_undo: Whether the undo entry should be a new item in the stack.
    """
    last_close = config.val.tabs.last_close
    count = self.widget.count()

    if last_close == "ignore" and count == 1:
        return

    self._remove_tab(tab, add_undo=add_undo, new_undo=new_undo)

    if count == 1:  # We just closed the last tab above.
        if last_close == "close":
            self.close_window.emit()
        elif last_close == "blank":
            self.openurl(QUrl("about:blank"), newtab=True)
        elif last_close == "startpage":
            for url in config.val.url.start_pages:
                self.openurl(url, newtab=True)
        elif last_close == "default-page":
            self.openurl(config.val.url.default_page, newtab=True)