{α : Type u} →
  {β : α → Type v} →
    [inst : BEq α] →
      {l : List ((a : α) × β a)} →
        {motive : Std.Internal.List.DistinctKeys l → Sort u_1} →
          (t : Std.Internal.List.DistinctKeys l) →
            ((distinct : List.Pairwise (fun a b => (a == b) = false) (Std.Internal.List.keys l)) → motive ⋯) → motive t