/// <summary>
        /// The method combines the population information of countries obtained from
        /// database and API in Dictionary, if the same country information in both
        /// data sources information from database is given preference.
        /// </summary>
        /// <returns>Dictionary with all the countries and its population
        /// key as country name and value as populations
        /// </returns>
        public Dictionary <string, int> GetCountryPopulations()
        {
            Dictionary <string, int> dict   = sqliteDbManagerImpl.GetCountryPopulations();
            StatsUtilityServices     helper = new StatsUtilityServices();

            IStatService statServiceFromConcrete = new ConcreteStatService();

            List <Tuple <string, int> > listFromConcrete = statServiceFromConcrete.GetCountryPopulations();

            helper.AddPopulationsToDictionary(dict, listFromConcrete);

            Console.WriteLine("Total results and merging both lists --------------------------------------size : " + dict.Count);
            return(dict);
        }