docs: def _python2_load_cpkl(fpath):
      """
      References:
          https://stackoverflow.com/questions/41720952/unpickle-sklearn-tree-descisiontreeregressor-in-python-2-from-python3
      """
      from lib2to3.fixes.fix_imports import MAPPING
      import sys
      import pickle
  
      # MAPPING maps Python 2 names to Python 3 names. We want this in reverse.
      REVERSE_MAPPING = {}
      for key, val in MAPPING.items():
          REVERSE_MAPPING[val] = key
  
      # We can override the Unpickler and loads
      class Python_3_Unpickler(pickle.Unpickler):
          """Class for pickling objects from Python 3"""
          def find_class(self, module, name):
              if module in REVERSE_MAPPING:
                  module = REVERSE_MAPPING[module]
              __import__(module)
              mod = sys.modules[module]
              klass = getattr(mod, name)
              return klass
  
      def load(fpath):
          with open(fpath, 'rb') as file_:
              data = Python_3_Unpickler(file_).load()
          return data