"ignoreHTTPSErrors": True not working . Getting pyppeteer.errors.PageError: net::ERR_PROXY_CERTIFICATE_INVALID error for self signed certificate

[silpi]

I am trying to launch Chromium and load an https://... url via proxy server
I am using pyppeteer==1.0.2

proxy_server = "https://198.18.xx.xx:443"
browser = await launch({'args': [f'--proxy-server={proxy_server}'], 'headless': False, "ignoreHTTPSErrors": True})

I am not able to load the url because of the Certificate error as mentioned below

pyppeteer.errors.PageError: net::ERR_PROXY_CERTIFICATE_INVALID at https://......

Note
I am able to load my web page properly when I am lunching the browser without proxy (that is when my proxy is set at /etc/hosts file of my local system)