Is there a standard library for python that implements Diffie-Hellman? I've taken a look at openssl wrapper in python pyopenssl and it doesn't cover it. I could not find it in NaCl or cryptography.io library either.
I have been looking for this as well. As far as I know, No, there are no standard libraries at this time.
Though you can refer to this post for a simple implementation.
Or this github page for a more developed poc
Edit: There appears to be a library for Diffie-Hellman now.