### What problem does this PR solve?
Update displayed_name to display_name
### Type of change
- [x] Refactoring
Co-authored-by: liuhua <10215101452@stu.ecun.edu.cn>
### What problem does this PR solve?
Introduced [beartype](https://github.com/beartype/beartype) for runtime
type-checking.
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Fix bugs in API
### Type of change
- [x] Bug Fix (non-breaking change which fixes an issue)
---------
Co-authored-by: liuhua <10215101452@stu.ecun.edu.cn>
### What problem does this PR solve?
fix bugs in test
### Type of change
- [x] Bug Fix (non-breaking change which fixes an issue)
---------
Co-authored-by: liuhua <10215101452@stu.ecun.edu.cn>