∀ {α : Type u} {β : α → Type v} [inst : BEq α] [inst_1 : Hashable α] [inst_2 : LawfulBEq α]
  (m m_1 : Std.DHashMap.Raw α β),
  m = m_1 → ∀ (a : α) (b b_1 : β a), b = b_1 → m.getThenInsertIfNew? a b = m_1.getThenInsertIfNew? a b_1