"""Print 'Hello World' every two seconds, using a coroutine."""
import asyncio
@asyncio.coroutine
def greet_every_two_seconds():
while True:
print('Hello World')
yield from asyncio.sleep(2)
if __name__ == '__main__':
loop = asyncio.get_event_loop()
loop.run_until_complete(greet_every_two_seconds())