How to use Python's built-in Logging with Asyncio (Permission Error)

I'm using a TimedRotatingFileHandler from logging to log to a new file each night. According to the logging docs:

The system will save old log files by appending extensions to the filename.

And it is when this happens that I get a Permission Error:

--- Logging error ---

PermissionError: [WinError 32] The process cannot access the file because it is being used by another process: 'C:\Users\lh\PythonIntegration\Connect\Logs\WS_API_integration_client' -> 'C:\Users\lh\PythonIntegration\Connect\Logs\WS_API_integration_client.2018-10-08_13-00'

I'm guessing that this has to do with the fact that I have a loop where I run asynchronous processes. But even when I tested it with only one logging event I get the permission error. Which means it's trying to change the extension of the same file it's writing to - hence the permission error. How do I tell logger to close the file so that it can add the extension to the filename?

This is my client.py

rotating_logger = logging.getLogger('ClientLogger')
rotating_logger.setLevel(logging.DEBUG)
handler = logging.handlers.TimedRotatingFileHandler(
              log_file, when = 'midnight',backupCount=30)              
formatter = logging.Formatter(fmt='%(asctime)s %(message)s', datefmt='%m/%d/%Y %I:%M:%S %p')
handler.setFormatter(formatter)
rotating_logger.addHandler(handler)

async def keep_alive(websocket):
    """
    Sends keep-alive message to the server. 
    """
    while websocket.open:            
        await websocket.send('hello')   
        await asyncio.sleep(60*1)

async def open_connection():
    loop = asyncio.get_event_loop()
    with concurrent.futures.ProcessPoolExecutor() as pool:
        async with websockets.connect( 
                'wss://{}:{}@host.net/api/ws'.format(user,pswd), 
                ssl=True, 
                max_queue = 1000) as websocket:
            """
            Keep connection alive.
            """            
            asyncio.ensure_future(keep_alive(websocket))

            """
            Handle messages from server
            """ 
            while True:  
                """
                Handle message from server.
                """
                message = await websocket.recv()
                if message.isdigit():
                    rotating_logger.info ('Keep alive message: {}'.format(str(message)))

if __name__ == '__main__':
    asyncio.get_event_loop().run_until_complete(open_connection())

from How to use Python's built-in Logging with Asyncio (Permission Error)