Python 3.15 Expert

The Python 3.15 Expert exam assesses deep, internals-level knowledge of CPython and the Python language — the tier aimed at engineers who reason about the runtime itself.

Topics covered include:

• Concurrency & the free-threaded build (PEP 703, 779; biased reference counting; internal locks; concurrent.interpreters)
• Memory model & GC (refcounting, cyclic GC, incremental GC, mimalloc, QSBR, immortal objects)
• Performance & profiling (specializing interpreter, JIT, tail-calling interpreter, profiling/Tachyon, frame pointers, sys.monitoring)
• Import system & runtime internals (meta path finders, lazy imports PEP 810, finalization)
• Advanced typing & metaprogramming (descriptors, metaclasses, PEP 649, TypedDict/TypeForm/disjoint bases)
• Build flags, ABI & C-API awareness (Py_GIL_DISABLED, Py_mod_gil, Stable ABI, -X options)
• Compatibility, deprecations & removals across 3.13-3.15

Passing this exam demonstrates expert-level command of Python 3.15, including the version's defining runtime changes.