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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 _init_go_sets(self, go_fins):
 """Get lists of GO IDs."""

        go_sets = []
        assert go_fins, "EXPECTED FILES CONTAINING GO IDs"
        assert len(go_fins) >= 2, "EXPECTED 2+ GO LISTS. FOUND: {L}".format(
            L=' '.join(go_fins))
        obj = GetGOs(self.godag)
        for fin in go_fins:
            assert os.path.exists(fin), "GO FILE({F}) DOES NOT EXIST".format(F=fin)
            go_sets.append(obj.get_usrgos(fin, sys.stdout))
        return go_sets