code: def flatten_reverse_dict(d):
      sep = "___"
      [flat_dict] = pd.json_normalize(d, sep=sep).to_dict(
          orient="records"
      )
      reversed_flat_dict = {
          v: tuple(k.split(sep)) for k, v in flat_dict.items()
      }
      return reversed_flat_dict
  
imports: from abc import abstractmethod
  from enum import Enum, auto
  import warnings
  import pandas
  import numpy
  import sklearn.base
  from pandas.api.types import is_object_dtype, is_string_dtype, is_numeric_dtype
  from pandas.core.dtypes.dtypes import CategoricalDtype
  from sklearn.base import BaseEstimator, TransformerMixin
  from sklearn.exceptions import NotFittedError
  from typing import Dict, List, Optional, Union
  from scipy.sparse import csr_matrix
  from sklearn.preprocessing import LabelEncoder
label_desc: Use image node_id 8 for calling a global function with example usage: flatten_reverse_dict(d) and returns: reversed_flat_dict