class_docstr: Variant of ChainMap that allows direct updates to inner scopes.
  
  Only works when all passed mapping are mutable.
class_docstr_tok: ["Variant","of","ChainMap","that","allows","direct","updates","to","inner","scopes",".","Only","works","when","all","passed","mapping","are","mutable","."]
code: def __setitem__(self, key: _KT, value: _VT) -> None:
      for mapping in self.maps:
          if key in mapping:
              mapping[key] = value
              return
      self.maps[0][key] = value
  
imports: from __future__ import annotations
  from collections import ChainMap
  import datetime
  import inspect
  from io import StringIO
  import itertools
  import pprint
  import struct
  import sys
  from typing import TypeVar
  import numpy
  from pandas._libs.tslibs import Timestamp
  from pandas.errors import UndefinedVariableError
label_desc: Use image node_id 1 for calling the DeepChainMap obj's underlying member method code with example usage: obj.__setitem__(key, value) without return types