def _init_taxids(taxid, taxids):
        """Return taxid set"""
        ret = set()
        if taxids is not None:
            if taxids is True:
                return True
            if isinstance(taxids, int):
                ret.add(taxids)
            else:
                ret.update(taxids)
        if taxid is not None:
            ret.add(taxid)
        if not ret:
            ret.add(9606)
            # pylint: disable=superfluous-parens
            print('**NOTE: DEFAULT TAXID STORED FROM gene2go IS 9606 (human)\n')
        return ret
Return taxid set