How to read and write 4K BKPSRAM?

I can't find the way in Demo samples.

__PWR_CLK_ENABLE();

HAL_PWR_EnableBkUpAccess();

HAL_PWR_EnableBkUpReg();

 __HAL_RCC_BKPSRAM_CLK_ENABLE();

above program can be used in F407, but can't be compiled in H750

https://community.st.com/s/question/0D50X0000ALwOvkSQF/i-can-not-use-backup-ram-for-stm32h743bi-is-there-any-application-note-or-source-code-for-backup-ram