// BookAuthor Check
 public bool bookAuthorCheck(string bookAuthor)
 {
     if (string.IsNullOrWhiteSpace(bookAuthor) || stringFirstLetterSpaceCheck(bookAuthor))
     {
         print.bookAuthorFirstNoSpaceMessage();
         return(true);
     }
     if (stringCheck(bookAuthor, 4))
     {
         print.bookAuthorErrorMessage();
         return(true);
     }
     return(false);
 }