/// <summary>
        /// Adds translations to the <see cref="FluentTranslationProvider"/>
        /// based on the key of the route component to translate;
        /// see <see cref="TranslationKeyGenerator"/>
        /// </summary>
        public TranslationBuilder ForKey(string key, Dictionary <string, string> cultureTranslationPairs)
        {
            IDictionary <string, string> translationsByKey;

            if (!_translations.TryGetValue(key, out translationsByKey))
            {
                _translations.Add(key, cultureTranslationPairs);
            }

            return(this);
        }