# File lib/active_support/vendor/i18n-0.3.7/i18n/backend/fast.rb, line 47
        def lookup(locale, key, scope = nil, options = {})
          return unless key
          init_translations unless initialized?

          return nil unless flattened_translations.has_key?(locale.to_sym)

          separator = options[:separator]
          if separator && I18n.default_separator != separator
            key   = cleanup_non_standard_separator(key, separator)
            scope = Array(scope).map{|k| cleanup_non_standard_separator(k, separator)} if scope
          end
          
          key = resolve_link(locale, key)
          key = (Array(scope) + [key]).join(I18n.default_separator) if scope
          flattened_translations[locale.to_sym][key.to_sym]
        end