Function with `admin_order_field` only sorts in one direction, with no arrows
|Reported by:||Owned by:||nobody|
|Has patch:||yes||Needs documentation:||no|
|Needs tests:||no||Patch needs improvement:||no|
admin_order_field on a function, it can only be sorted in one direction (ascending), and no arrows will be displayed when sorted.
my_function.admin_order_field = 'model_field'
This will result in the column showing up correctly, and it is a link which sorts, but it does not work, as described above.