[WTA] How to duplicate 'convert' function from lead entity to other custom entity

[ming]

Hi guys,
i have an issue right now. we're trying to using the convert function that only have from lead entity which is great. but now, we going to use the convert function to others custom entity.
we're already copy the .js file, .php file and some .json file from lead entity folder to the custom entity folder. but seems still not working out.
we actually found the getConvertAttribute in lead.php . we already copy this function to our custom entity and output will be like as the picture below.