What's Changed
- Implement many methods: `count`, `difference`, `divide_at`, `filter`, `first`, `from_empty`, `from_frozenset`, `from_iterable`, `from_list`, `from_set`, `from_tuple`, `get_first`, `get_last`, `get_nth`, `get_one`, `index_of`, `indices_of`, `intersection`, `is_disjoint`, `is_empty`, `is_equal_as_set`, `is_non_empty`, `is_subset`, `is_superset`, `last`, `map`, `nth`, `one`, `popped`, `popped_n`, `pushed`, `pushed_all`, `records`, `reduce`, `reversed`, `search_all`, `search_first`, `search_last`, `shifted`, `shifted_n`, `size`, `slice`, `sorted`, `symmetric_difference`, `to_dict`, `to_dict_of_list`, `to_frozenset`, `to_list`, `to_set`, `to_tuple`, `union`, `unique`, `unshifted`, `unshifted_all`
**Full Changelog**: https://github.com/kitsuyui/python-richset/compare/v0.0.1...v0.1.0