Portable — Python 3.13 Changes

def process_data(data: list[str] | list[int]): if is_string_list(data): # Type checker knows data is list[str] here print(f"String list: ', '.join(data)") else: # Type checker knows data is list[int] here print(f"Sum of ints: sum(data)") def handle_status(status: Literal["active", "inactive", "pending"]) -> str: match status: case "active": return "User is active" case "inactive": return "User is inactive" case "pending": return "User pending approval" case _: assert_never(status) # Type checker verifies all cases handled 6. Performance Improvements Python 3.13 includes a new JIT compiler (experimental) and optimized internals.

def benchmark_fibonacci(): n = 35

async def main_new_way(): # Python 3.13 - same syntax, but ~10-15% faster # Task creation and scheduling overhead reduced async with asyncio.TaskGroup() as tg: tasks = [tg.create_task(process_item(i)) for i in range(1000)] return [task.result() for task in tasks] async def benchmark(): start = time.perf_counter() await main_old_way() old_time = time.perf_counter() - start python 3.13 changes

print("✓ Running Python 3.13+")