class_docstr: Base class for tracked locals and stack values
  
  VariableTracker instances are immutable and should be copied in
  order to change them.
class_docstr_tok: ["Base","class","for","tracked","locals","and","stack","values","VariableTracker","instances","are","immutable","and","should","be","copied","in","order","to","change","them","."]
code: def maybe_fx_node(self):
      try:
          proxy = self.as_proxy()
          import torch.fx
  
          if isinstance(proxy, torch.fx.Proxy):
              return proxy.node
          return None
      except NotImplementedError:
          return None
  
imports: import collections
  from enum import Enum
  from typing import Any, Callable, Dict, List
  from ..None import variables
  from ..current_scope_id import current_scope_id
  from ..exc import unimplemented
  from ..source import AttrSource, Source
  from ..utils import identity, istype
label_desc: Use image node_id 14 for calling the VariableTracker obj's underlying member method code with example usage: obj.maybe_fx_node() and returns: None, proxy, None