/// <summary>
        /// Checks the that authors file does not contain This book title.
        /// </summary>
        /// <param name="filePath">The path to the authors file.</param>
        /// <param name="bookTitle">Title of book to check if contained in authors file all ready..</param>
        /// <returns></returns>
        private bool CheckThatAuthorsFileDoesNotContainThisBookTitle(string filePath, string bookTitle)
        {
            this._msgBox.NameOfMethod = MethodBase.GetCurrentMethod().Name;

            var clsInput = new InputClass();

            var bookData = clsInput.ReadAllBookTitlesFromAuthorsFile(filePath);

            if (!bookData.Any())
            {
                return(false);
            }

            var titleOp = new TitlesOperationClass();
            var titles  = titleOp.GetBookTitleFromBookData(bookData);

            if (!titles.Any())
            {
                return(false);
            }

            var valid = new ValidationClass();

            // true if book title is all ready contained in authors file else false.
            return(valid.ValidateAuthorsFileDoesNotContainThisBookTitle(titles, bookTitle));
        }