ArgumentBuilder { public ArgumentBuilder callback(Boolean callback) { this.callback = callback; return this; }  ArgumentBuilder index(Integer index); ArgumentBuilder type(String type); ArgumentBuilder callback(Boolean callback); ArgumentConfig build();  }
@Test void callback() { ArgumentBuilder builder = new ArgumentBuilder(); builder.callback(true); Assertions.assertTrue(builder.build().isCallback()); builder.callback(false); Assertions.assertFalse(builder.build().isCallback()); }