@Override
    public Void visitModifyFrontendHostClause(ModifyFrontendAddressClause clause, ConnectContext context) {
        checkModifyHostClause(clause.getSrcHost(), clause.getDestHost());
        return null;
    }
@Test
    public void testVisitModifyFrontendHostClause() {
        mockNet();
        AlterSystemStmtAnalyzer visitor = new AlterSystemStmtAnalyzer();
        ModifyFrontendAddressClause clause = new ModifyFrontendAddressClause("test", "fqdn");
        Void result = visitor.visitModifyFrontendHostClause(clause, null);
    }