∀ {α : Type u} {β : α → Type v} [inst : Ord α] [Std.TransOrd α] [inst_2 : BEq α] [Std.LawfulBEqOrd α]
  {l : List ((a : α) × β a)},
  Std.Internal.List.DistinctKeys l →
    ∀ {k : α} {v : β k},
      Std.Internal.List.maxKey (Std.Internal.List.insertEntry k v l) ⋯ =
        (Std.Internal.List.maxKey? l).elim k fun k' => if (compare k' k).isLE = true then k else k'