[realpython-bot]

Brings hashtable/ in line with the Python 3.15 update of Build a Hash Table in Python With TDD and the new video course built from it.

What changed

• BLANK (the prototype steps 02-05) and DELETED (linear probing, autoresize, load factor) are built-in sentinel() objects instead of object().
• HashTable.pairs in 01_hashtable_prototype/07_use_defensive_copying returns copy.deepcopy(...) of the list: a shallow copy still shares mutable values, so a caller could change the table through it (a reader's comment on the tutorial). From folder 08 on, .pairs is a set, whose members must be hashable, so a shallow copy is enough there.
• HashTable.pairs in 05_separate_chaining unpacks the buckets in a set comprehension, {*bucket for bucket in self._buckets} (PEP 798).
• requirements.txt pins pytest 9.1.1 and pytest-unordered 0.8.0, resolved for Python 3.15.
• The README says the code requires Python 3.15 or later, and creates the venv with python3.15.
• pyproject.toml excludes hashtable from ruff, like python315-frozendict/, python315-lazy-imports, and python315-new-features. Ruff 0.14.1 targets py314, where sentinel is undefined (F821) and unpacking in a comprehension is a syntax error.

The folders keep their structure (match with _find()), as the tutorial describes them.

How it was verified

• A fresh Python 3.15.1 venv from requirements.txt. Every folder's tests pass with the README's commands, with the same counts as before: the prototype steps 01-12 (PYTHONHASHSEED=128) give 3, 6, 14, 16, 17, 18, 20, 29, 34, 38, 42, and 49 passed, then 57, 58, 67, 62, and 62 passed for 02-06.
• hash_distribution.py runs.
• uvx ruff@0.14.1 check . and format --check . are clean.

The tutorial's own update is a separate, unpublished draft in the CMS that uses this code: python-hash-table-update (an [UPDATE] clone of the live post).