def reserveBook(self,name, student_id, book_title, days):
for book in Catalog.books_list:
if book.title == book_title and len(book.book_item) != 0:
book_item = book.book_item.pop()
book.total_count -= 1
Catalog.updateIssuerInfo(book_item, name, student_id, days)
Catalog.addToReservedList(book_item)
return book_item
else:
print("The book you're trying to reserve is unavailable.")
