def unset_value(self):
        """
        Removes any user value from the symbol, as if the symbol had never
        gotten a user value via Kconfig.load_config() or Symbol.set_value().
        """
        if self.user_value is not None:
            self.user_value = None
            self._rec_invalidate_if_has_prompt()

        Removes any user value from the symbol, as if the symbol had never
        gotten a user value via Kconfig.load_config() or Symbol.set_value().
        
buildroot-external/scripts/kconfiglib.py