def error(message, level="error", exit_code=1, **kwargs):
    kwargs["fg"] = kwargs.get("fg", "red")
    click.secho(u"error: {}".format(message), **kwargs)
    sys.exit(exit_code)
def set_submodule(self, submodule: 'Submodule') -> None:
        """Set this instance's submodule. It must be called before
        the first write operation begins"""
        self._smref = weakref.ref(submodule)