# TypedDict ReadOnly class Config(TypedDict): name: str version: ReadOnly[int]

cfg: Config = "name": "test", "version": 1 cfg["name"] = "new" # OK # cfg["version"] = 2 # Type error if == " main ": main() Final Notes Python 3.13 is a solid, incremental release. The experimental JIT is exciting but not yet for production unless you can test heavily. Most code written for 3.12 will run unchanged (except removed modules). Upgrade for the REPL, error messages, and typing improvements. For GIL-free Python, wait for 3.14 (2026).

# New pathlib src = Path("temp.txt") src.write_text("hello") dst = Path("temp_copy.txt") src.copy(dst) # New in 3.13 print(dst.read_text())