code: def support_index_min(self, tags=None):
          # type: (Optional[List[Pep425Tag]]) -> Optional[int]
          
          if tags is None:  # for mock
              tags = pep425tags.get_supported()
          indexes = [tags.index(c) for c in self.file_tags if c in tags]
          return min(indexes) if indexes else None
docs: Return the lowest index that one of the wheel's file_tag combinations
          achieves in the supported_tags list e.g. if there are 8 supported tags,
          and one of the file tags is first in the list, then return 0.  Returns
          None is the wheel is not supported.