code: def _keep_alive(x, memo):
      """Keeps a reference to the object x in the memo.
  
      Because we remember objects by their id, we have
      to assure that possibly temporary objects are kept
      alive by referencing them.
      We store a reference at the id of the memo, which should
      normally not be used unless someone tries to deepcopy
      the memo itself...
      """
      try:
          memo[id(memo)].append(x)
      except KeyError:
          # aha, this is the first one :-)
          memo[id(memo)] = [x]
  
file_path: catboost/contrib/tools/python3/src/Lib/copy.py
imports: import types
  import weakref
  from copyreg import dispatch_table
label_desc: Use image node_id 9 for calling a global function with example usage: _keep_alive(x, memo) without return types