∀ {α : Type u} {β : α → Type v} (m : Std.DHashMap.Internal.Raw₀ α β) [inst : BEq α] [inst_1 : Hashable α] [EquivBEq α]
  [LawfulHashable α] [inst_4 : Inhabited α],
  (↑m).WF →
    ∀ {k a : α} {v : β k},
      (m.insertIfNew k v).getKey! a = if (k == a) = true ∧ m.contains k = false then k else m.getKey! a