import asyncio
from itertools import count

async def position_stream():
    try:
        for position in count():
            await asyncio.sleep(1)
            yield position
    finally:
        print("position stream cancelled")

async def altitude_stream():
    try:
        for altitude in count():
            await asyncio.sleep(1)
            yield altitude
    finally:
        print("altitude stream cancelled")

async def print_position():
    async for position in position_stream():
        print(f"position: {position}")

        if position == 2:
            cleanup()

async def print_altitude():
    async for altitude in altitude_stream():
        print(f"altitude: {altitude}")

def cleanup():
    loop = asyncio.get_event_loop()
    asyncio.ensure_future(loop.shutdown_asyncgens())
    loop.close()

if __name__ == '__main__':
    try:
        asyncio.ensure_future(print_position())
        asyncio.ensure_future(print_altitude())
        asyncio.get_event_loop().run_forever()
    except KeyboardInterrupt:
        pass