How Pyppeteer Python connect to proxy server?

Question

Regarding this answer: Python pyppeteer, how to use a socks proxy the proxy server for PyPpeteer in Python should be this:

args = [
 '--proxy-server=185.199.199.156:888',
 '--disable-notifications',
 '--start-maximized'
]  
`browser = await launch({
                    'headless': False,
                    'slowMo': randomWait,
                    'options': {'args': args}, 
                    'executablePath': _executablePath,
                    'userDataDir': _userDataDir,
                    'defaultViewport': None
})

BUT for me it throw this error:
'str' object has no attribute 'get'

I tried this:
'--proxy-server=http://185.199.229.156:7492'
'--proxy-server=https://185.199.229.156:7492'
'--proxy-server=185.199.229.156:7492'

Always the same error and pyppeteer can not use proxy.