public void AddBook(Book book)
{
if(!_bookList.Contains(book))
{
_bookList.ToList().Add(book);
}
}
public void UpdateBook(Book book)
{
if(!_bookList.Contains(book))
{
_bookList.ToList().Add(book);
}
else
{
_bookList.ToList().Remove(book);
_bookList.ToList().Add(book)
}
}