private void RemoveCityFromSelectedCollection(CityModel inCityModel)
 {
     if (CheckedCitiesList != null)
     {
         if (CheckedCitiesList.Contains(inCityModel))
         {
             CheckedCitiesList.Remove(inCityModel);
             inCityModel.PropertyChanged -= InCityModel_PropertyChanged;
         }
     }
 }
 //Work with Models functions
 #region Add & Remove City from Checked Cities List
 private void AddCityToSelectedCollection(CityModel inCityModel)
 {
     if (CheckedCitiesList != null)
     {
         if (!CheckedCitiesList.Contains(inCityModel))
         {
             CheckedCitiesList.Add(inCityModel);
             inCityModel.PropertyChanged += InCityModel_PropertyChanged;
         }
     }
 }