Data Structures, Algorithms, Data Engineering, Data Science, Doubly Linked List.
self.current_page = new_page def back(self): if self.current_page and self.current_page.prev: self.current_page = self.current_page.prev return self.current_page.url else: return "No previous pages in history." def forward(self): if self.current_page and self.current_page.next: self.current_page =