def __init__(self, apps=None, *args, **kwargs):
        # List of locations with static files
        self.locations = []
        # Maps dir paths to an appropriate storage instance
        self.storages = SortedDict()
        if not isinstance(settings.STATICFILES_DIRS, (list, tuple)):
            raise ImproperlyConfigured(
                "Your STATICFILES_DIRS setting is not a tuple or list; "
                "perhaps you forgot a trailing comma?")
        for root in settings.STATICFILES_DIRS:
            if isinstance(root, (list, tuple)):
                prefix, root = root
            else:
                prefix = ''
            if os.path.abspath(settings.STATIC_ROOT) == os.path.abspath(root):
                raise ImproperlyConfigured(
                    "The STATICFILES_DIRS setting should "
                    "not contain the STATIC_ROOT setting")
            if self.locations not in (prefix, root):
                self.locations.append((prefix, root))
        for prefix, root in self.locations:
            filesystem_storage = FileSystemStorage(location=root)
            filesystem_storage.prefix = prefix
            self.storages[root] = filesystem_storage
        super(FileSystemFinder, self).__init__(*args, **kwargs)
dataset/ETHPy150Open AppScale/appscale/AppServer/lib/django-1.4/django/contrib/staticfiles/finders.py/FileSystemFinder.__init__/swapped operands of `not in`