protected String addIndent(String line, int indent) {
    return "  ".repeat(Math.max(0, indent)) + line + "\n";
  }
@Test
    public void testAddIndent() {
        MessageCodeGen messageCodeGen = new MessageCodeGen();
        assertEquals(messageCodeGen.addIndent("add indentation", 3), "      add indentation\n");
        assertEquals(messageCodeGen.addIndent("add indentation", 0), "add indentation\n");
    }