# File lib/active_support/vendor/i18n-0.4.1/i18n/backend/memoize.rb, line 31
        def lookup(locale, key, scope = nil, options = {})
          flat_key  = I18n::Backend::Flatten.normalize_flat_keys(locale,
            key, scope, options[:separator]).to_sym
          flat_hash = memoized_lookup[locale.to_sym]
          flat_hash.key?(flat_key) ? flat_hash[flat_key] : (flat_hash[flat_key] = super)
        end