Return sorted Grouper namedtuples if there are user GO IDs underneath.

def get_ntgos_sorted(self, hdrgos):
        """Return sorted Grouper namedtuples if there are user GO IDs underneath."""
        go2nt = self.grprobj.go2nt
        return sorted([go2nt[go] for go in hdrgos if go in go2nt], key=self.fncsortnt)