code: function get(city, _options) {
        extend(options, _options, {city: city});
  
        getWeather = $q.when(getWeather || angular.copy(getCache()) || getWeatherFromServer(city));
  
        // Clear the promise cached, after resolve or reject the promise. Permit access to the cache data, when
        // the promise excecution is done (finally).
        getWeather.finally(function getWeatherFinally() {
          getWeather = undefined;
        });
  
        return getWeather;
      }
docs: Return the promise with the category list, from cache or the server.
  
  @param city - string
  The city name. Ex: Houston
  @param _options - object
  The options to handle.
  refresh: activate to get new weather information in interval
  of delay time.
  delay: interval of time in miliseconds.
  
  @returns {Promise}