code: def _fetch_type_sub(cls, cls_in, match):
          
  
          if match.group(cls._SUBMATCH_INDEX_TYPE_SUB):
              return cls._str_to_type(
                  cls_in,
                  match.group(cls._SUBMATCH_INDEX_TYPE_SUB)
              )
          else:
              return None
docs: :type cls_in: type
          :type match: _sre.SRE_Match
  
          :rtype: type