code: def get_hdrgo2usrgos(self, hdrgos):
          
          get_usrgos = self.hdrgo2usrgos.get
          hdrgos_actual = self.get_hdrgos().intersection(hdrgos)
          return {h:get_usrgos(h) for h in hdrgos_actual}
docs: Return a subset of hdrgo2usrgos.