//</Snippet4>

        //<Snippet5>
        static void GetEnumerator()
        {
            try
            {
                System.Configuration.Configuration config =
                    ConfigurationManager.OpenExeConfiguration(
                        ConfigurationUserLevel.None);

                ConfigurationSectionCollection sections =
                    config.Sections;

                IEnumerator secEnum =
                    sections.GetEnumerator();

                //<Snippet6>
                int i = 0;
                while (secEnum.MoveNext())
                {
                    string setionName = sections.GetKey(i);
                    Console.WriteLine(
                        "Section name: {0}", setionName);
                    i += 1;
                }
                //</Snippet6>
            }
            catch (ConfigurationErrorsException err)
            {
                Console.WriteLine(err.ToString());
            }
        }
        private IEnumerable ParserProcessing(object config)
        {
            object[] sectionKeys = null;
            if (config == null)
            {
                throw new ArgumentNullException(nameof(config));
            }
            if (!(config is Configuration reducedConfig))
            {
                return(null);
            }
            ConfigurationSectionCollection sections = reducedConfig.Sections;

            sectionKeys = new object[sections.Count];
            if (sections.Count <= 0)
            {
                return(null);
            }
            for (var i = 0; i < sections.Count; i++)
            {
                var sectionKey = sections.GetKey(i);
                sectionKeys[i] = sectionKey;
                Logger.LogInformation($"{sectionKey} был добавлен");
            }
            return(sectionKeys);
        }