message: Building the whl fails with Extension not found
  If using Extension, you best import it
  Fix break by commit:
diff: @@ -35,6 +35,7 @@ import re
  import sys
  from setuptools import Command
  +from setuptools import Extension
  from setuptools import find_packages
  from setuptools import setup
  from setuptools.command.install import install as InstallCommandBase
  