How do I implement a correct HAL_I2S_MSP_INIT function

[GHalb]

Hi I'm trying to get a codec up and running in full duplex using I2S with an STM32F407ZGT6 as MCU. I configure the project using STM32CubeIDE and thus also STM32CubeMx. I have got a skeleton generated but the function HAL_I2S_MSP_INIT that is generated states that the user should implement it - but unfortunately I'm clueless as to what it should do - so any pointer to what is supposed to happen in that function will be greatly appreciated.