How to use vuetify 3 data table sort

Question

I'm on Vuetify 3 and i have a v-data-table with some data inside and I'd like to be able to add a custom sort on some columns. I've tried to add it in the header by putting a function in "sort" but I can't get the information back.

for test purpose i try with a return random and the sort function works fine.

what i want to do (in the headers):

{
  title : "Title of the column",
  key: "myKey",
  sortable: true,
  sort: (a,b) => {
    //sorting algo
    return sortingResult
   },
},

but a and b are undefined