public IEnumerable <string> GetErrosToCreate() { if (string.IsNullOrEmpty(FirstName) || FirstName.All(char.IsWhiteSpace)) { yield return("First Name cannot be empty."); } if (string.IsNullOrEmpty(LastName) || LastName.All(char.IsWhiteSpace)) { yield return("Last Name cannot be empty."); } if (string.IsNullOrEmpty(Document) || Document.All(char.IsWhiteSpace)) { yield return("Document cannot be empty."); } }