code: def wheel_version(source_dir):
      # type: (Optional[str]) -> Optional[Tuple[int, ...]]
      
      try:
          dist = [d for d in pkg_resources.find_on_path(None, source_dir)][0]
  
          wheel_data = dist.get_metadata('WHEEL')
          wheel_data = Parser().parsestr(wheel_data)
  
          version = wheel_data['Wheel-Version'].strip()
          version = tuple(map(int, version.split('.')))
          return version
      except Exception:
          return None
docs: Return the Wheel-Version of an extracted wheel, if possible.
  
      Otherwise, return None if we couldn't parse / extract it.