Answer:
class Books(object):
 books_count = 0
 books = {}
 #classmethod
 def book_count(cls):
 cls.books_count +=1
 #classmethod
 def add(cls, title, author, year, status):
 if cls.books_count < 100:
 cls.book_count()
 cls.books[title] = [author, year, status]
 else:
 print("Book register has reached it's limit.")
 #classmethod
 def check(cls, book_name):
 return cls.books.get(book_name)
please replace the '#' with the 'at' sign.
Step-by-step explanation:
The python class defines several class methods namely; add, check and book_count. The add method adds books to the book dictionary in the class as a class attribute, the check method check for the presents of a book title in the book dictionary while the book_count method adds one to the books_count class variable which checks the dictionary size.