∀ {α : Type u} {β : Type v} {γ : Type w} [inst : BEq α] [inst_1 : Hashable α] {m : Std.HashMap.Raw α β} [EquivBEq α]
  [LawfulHashable α] [inst_4 : Inhabited γ] {f : α → β → γ} {k k' : α},
  m.WF → m.getKey? k = some k' → (Std.HashMap.Raw.map f m)[k]! = (Option.map (f k') m[k]?).get!