input: Write a python function to create a new Book object and save it to the database.
  assert create_book("The Great Gatsby", "F. Scott Fitzgerald", "1234567890123", "1925-04-10", "A novel about the American dream.") is not None
  assert create_book("To Kill a Mockingbird", "Harper Lee", "1234567890124", "1960-07-11", "A novel about racial injustice.") is not None
  assert create_book("", "", "", "", "") is None
output: def create_book(title, author, isbn, publication_date, description):
      if not title or not author or not isbn or not publication_date or not description:
          return None
  
      # Assuming we have a Book model with a save method
      class Book:
          def __init__(self, title, author, isbn, publication_date, description):
              self.title = title
              self.author = author
              self.isbn = isbn
              self.publication_date = publication_date
              self.description = description
  
          def save(self):
              # Placeholder for saving the book to a database
              pass
  
      new_book = Book(title, author, isbn, publication_date, description)
      new_book.save()
      return new_book