def METHOD_NAME():
    global _default_theme
    if _default_theme:
        return
    _default_theme = Gtk.IconTheme.get_default()
    for p in _look_for_application_icons():
        _default_theme.prepend_search_path(p)
        break  # only prepend one path - that's sufficient
    if _log.isEnabledFor(_DEBUG):
        _log.debug('icon theme paths: %s', _default_theme.get_search_path())
    if gtk.battery_icons_style == 'symbolic':
        global TRAY_OKAY
        TRAY_OKAY = TRAY_INIT  # use monochrome tray icon
        if not _default_theme.has_icon('battery-good-symbolic'):
            _log.warning('failed to detect symbolic icons')
            gtk.battery_icons_style = 'regular'
    if gtk.battery_icons_style == 'regular':
        if not _default_theme.has_icon('battery-good'):
            _log.warning('failed to detect icons')
            gtk.battery_icons_style = 'solaar'