# File lib/active_support/vendor/i18n-0.4.1/i18n.rb, line 251
    def normalize_keys(locale, key, scope, separator = nil)
      separator ||= I18n.default_separator

      keys = []
      keys.concat normalize_key(locale, separator)
      keys.concat normalize_key(scope, separator)
      keys.concat normalize_key(key, separator)
      keys
    end