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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 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