def missing_used_tree(locale)
      used_tree(strict: true).select_keys do |key, _node|
        locale_key_missing?(locale, key)
      end.set_root_key!(locale, type: :missing_used)
    end
def missing_used_tree(locale)
      used_tree(strict: true).select_keys do |key, _node|
        locale_key_missing?(locale, key)
      end.set_root_key!(locale, type: :missing_used)
    end
keys used in the code missing translations in locale