Get material color form .mtl

Hi, I've tried different methods to get material colors defined in mtl such as ka, kd and ks via your assimp pkg but all failed.
I checked the c pkg of assimp and found the Get() method of aiMaterial is defined for that, would you please tell me which methods shall I use in your pkg? And if you can give me some examples for that. Thank you! @raedatoui 