- Introduce `get_recent_cities` to filter out cities that have been recently generated weather arts.
- Update `select_cities` method to exclude recent cities from the selection process, ensuring diversity in the generated arts.
- Modify the `select_countries` method to maintain its functionality while integrating recent city filtering.
This update enhances the system's ability to select active cities efficiently, reducing redundancy and improving the variety of generated weather arts by avoiding recent candidates.