ExampleImporter.cs

public class ExampleImporter
{
   private readonly IExampleService _exampleService;
   public ExampleImporter(IExampleService exampleService)
   {
      _exampleService = exampleService;
   }
   
   public async Task Import()
   {
      var items = await _exampleService.Get();
      foreach (var item in items)
      {
         string valMessage;
         if (!IsValid(item, out valMessage))
         {
            // TODO: Log validation message.
            continue;
         }
         var example = GetFromDb(item);
         if (example == null)
         {
            example = new Example();
            // TODO: Update example properties from item.
            Add(example);
         }
         else
         {
            // TODO: Update data properties.
            Update(example);
         }
      }
      Commit();
   }

   private Example GetFromDb(ExternalExampleModel externalExample)
   {
      // TODO Get data from db if exist.
   }

   private void Add(Example example)
   {
      // TODO: Add item to db
   }

   private void Update(Example example)
   {
      // TODO: Update item
   }
   
   private bool IsValid(ExternalExampleModel data, out string validationMessage)
   {
      // TODO: Validate item
      validationMessage = "";
      return true;
   }
   private void Commit()
   {
      // TODO: Commit changes
   }
}