collections and functools helpers: `defaultdict`, `Counter`, `deque`, `namedtuple`, `partial`, `reduce`, and `lru_cache`
These helpers reduce boilerplate for grouping, counting, queue behavior, lightweight record types, partial application, reduction, and memoization.
- `Counter` counts fast
- `deque` is strong for queues
- `lru_cache` adds memoization with little code
collections and functools helpers: `defaultdict`, `Counter`, `deque`, `namedtuple`, `partial`, `reduce`, and `lru_cache`