Correct, PEP 543 won't land in Python 3.7 because neither me nor Cory have the resources to land it. However I want all changes and new additions to the SSL module to follow PEP 543 so I can provide a PEP 543-compatible interface in the near future (3.8 or 3.9). We need a proper certificate class anyway to address other issues and feature requests. I don't want to have three ways to load certificates, especially when it involves more C code.