code: def standardize_mapping(into):
      
      if not inspect.isclass(into):
          if isinstance(into, collections.defaultdict):
              return partial(
                  collections.defaultdict, into.default_factory)
          into = type(into)
      if not issubclass(into, abc.Mapping):
          raise TypeError('unsupported type: {into}'.format(into=into))
      elif into == collections.defaultdict:
          raise TypeError(
              'to_dict() only accepts initialized defaultdicts')
      return into
docs: Helper function to standardize a supplied mapping.
  
      .. versionadded:: 0.21.0
  
      Parameters
      ----------
      into : instance or subclass of collections.abc.Mapping
          Must be a class, an initialized collections.defaultdict,
          or an instance of a collections.abc.Mapping subclass.
  
      Returns
      -------
      mapping : a collections.abc.Mapping subclass or other constructor
          a callable object that can accept an iterator to create
          the desired Mapping.
  
      See Also
      --------
      DataFrame.to_dict
      Series.to_dict