def __init__(self, *args, **kwargs):
        """
        Stacked dynamic inlines won't work without grappelli
        installed, as the JavaScript in dynamic_inline.js isn't
        able to target each of the inlines to set the value of
        the order field.
        """
        grappelli_name = getattr(settings, "PACKAGE_NAME_GRAPPELLI")
        if settings.INSTALLED_APPS not in grappelli_name:
            error = "StackedDynamicInlineAdmin requires Grappelli installed."
            raise Exception(error)
        super(StackedDynamicInlineAdmin, self).__init__(*args, **kwargs)
dataset/ETHPy150Open stephenmcd/mezzanine/mezzanine/core/admin.py/StackedDynamicInlineAdmin.__init__/swapped operands of `not in`