import asyncio
import aiohttp

async def checkItOut(session):
    async with session.post(CHECKOUT, data=CHECKOUT_DATA, headers=CHECKOUT_HEADERS ) as response:
        return response.text()

loop = asyncio.get_event_loop()
async with aiohttp.ClientSession(loop=loop) as session:
    loop.run_until_complete(checkItOut(session))
loop.close()