Python learning tracks

What mypy --strict actually enables, what it misses, how to read its errors — and a placement diagnostic. Start here: in python mode the type checker is half the grade.

Generics, protocols, narrowing, variance and Final. The hard prerequisite for every other python track.

Protocols vs ABCs, overloads, TypeIs, ParamSpec, self types and the parts of the type system that fight back.

Dataclasses, TypedDict, NamedTuple, enums and validation at the boundary — making illegal states unrepresentable.

Structural pattern matching, f-string internals, PEP 695 syntax and the version-gated features worth adopting.

itertools, functools, collections, pathlib, decimal, datetime — the batteries you already shipped and mostly do not use.

Exception hierarchies as API, chaining, ExceptionGroup, retry budgets, deprecation and typing the error path.

Generators, iterators, itertools pipelines and the memory profile of doing the same work lazily.

pytest layout, fixtures, parametrisation, injection over patching, property-based testing and typed test suites.

asyncio as it is in 2026: TaskGroup, asyncio.timeout, cancellation semantics, backpressure and structured concurrency.

The GIL, free-threading, multiprocessing start methods, subinterpreters and what parallelism actually costs.

The object model, refcounting and the GC, __slots__, big-O traps, timeit and deterministic profiling.

Import machinery, cycles, __all__, layering, build backends, lockfiles and the CI gate order.

Encoding, serialisation, clocks, filesystems, subprocesses — everywhere your typed core meets an untyped world.

Multi-defect, multi-track exercises. Each one needs several earlier tracks at once.