The function call will not succeed.

Paginator.cursor_for_record(_post :: %Post{_ => _}, [{:id, :asc}]) ::
  :ok
def a() do
  :ok
end

will never return since it differs in arguments with
positions 2nd from the success typing arguments:

(any(), [atom()])

Paginator.cursor_for_record(%Paginator.Customer{id: 1, name: "Alice"}, [id: :asc, name: :desc])