code: def flatten(self) -> Set[str]:
      return set(
          itertools.chain(
              *[
                  [b] if isinstance(b, str) else b.flatten()
                  for b in self.children
              ]
          )
      )
  
imports: import itertools
  from collections.abc import Sequence
  from typing import List, Optional, Set, Tuple, Union
  import torch
label_desc: Use image node_id 9 for calling the AdapterCompositionBlock obj's underlying member method code with example usage: obj.flatten() and returns: set