Add a new variant (board) of STM8L151 to arduino core

I developed a new board based on STM8L151K6. I use this chip because it has low pin count (32 pin), easy to solder and low-power. Based on this document, [login to view URL], one of boards available is Nucleo STM8L152R8. I follow this tutorial ([login to view URL](board)) to add a new variant (board). But, it is failed. I am looking for freelancer to add a new variant of my board. I will provide the schematic of the board, it is just a minimum system. The result will be put on public github.