It is quite normal to have an internal PKI based on the Microsoft AD Certificate Services, which work great with Windows, but not so much on other OSes. Users of other OSes must often manually create a CSR and then use the Certificate Services web page (certsrv) to get a certificate. This is not ideal, as it is a manual and time consuming (and creating a csr with OpenSSL on the command line is confusing and complicated.)
This is a simple litle Python client for the certsrv page, so that Python programs can get certificates without manual operation.
$ pip install certsrv
Or, if you want NTLM support:
$ pip install certsrv[ntlm]
See Documentation