MechanicalSoup - SSL: CERTIFICATE_VERIFY_FAILED behind proxy

[5u88u]

I am trying to submit a form and process the response using mechanicalsoup.

I am able to do it successfully without a proxy. But when I try to run the same code behind the proxy I am getting the following error
requests.exceptions.SSLError: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:645)

I have created the proxy dict and assigned it as

browser = mechanicalsoup.StatefulBrowser()
browser.session.proxies = proxies
browser.open(url)

Please guide me where am I going wrong.

Thanks.

Regards,
Subramanian S.