∀ {α : Type u} {β : Type v} [inst : BEq α] [inst_1 : Hashable α] [EquivBEq α] [LawfulHashable α] [inst_4 : Inhabited α]
  {l : List (α × β)} {k k' : α},
  (k == k') = true →
    List.Pairwise (fun a b => (a.1 == b.1) = false) l →
      k ∈ List.map Prod.fst l → (Std.HashMap.Raw.ofList l).getKey! k' = k