∀ {α : Type u} {β : Type v} {cmp : α → α → Ordering} [Std.TransCmp cmp] {l : List (α × β)} {k k' : α},
  cmp k k' = Ordering.eq →
    ∀ {v : β},
      List.Pairwise (fun a b => ¬cmp a.1 b.1 = Ordering.eq) l → (k, v) ∈ l → (Std.TreeMap.ofList l cmp)[k']? = some v