code: def itersubdirs(self, pattern=None, abspath=False):
          
          if pattern is not None:
              globster = Globster([pattern])
          for root, dirs, files in self.walk():
              for d in dirs:
                  if pattern is None or (pattern is not None and globster.match(d)):
                      if abspath:
                          yield os.path.join(root, d)
                      else:
                          yield self.relpath(os.path.join(root, d))
docs: Generator for all subdirs (except excluded).
  
          :type pattern: str
          :param pattern: Unix style (glob like/gitignore like) pattern