Return usrgos under provided hdrgos.

def get_usrgos_g_hdrgos(self, hdrgos):
        """Return usrgos under provided hdrgos."""
        usrgos_all = set()
        if isinstance(hdrgos, str):
            hdrgos = [hdrgos]
        for hdrgo in hdrgos:
            usrgos_cur = self.hdrgo2usrgos.get(hdrgo, None)
            if usrgos_cur is not None:
                usrgos_all |= usrgos_cur
            if hdrgo in self.hdrgo_is_usrgo:
                usrgos_all.add(hdrgo)
        return usrgos_all