code: def ensure_key_mapped(values, key: Callable | None, levels=None):
      """
      Applies a callable key function to the values function and checks
      that the resulting value has the same shape. Can be called on Index
      subclasses, Series, DataFrames, or ndarrays.
  
      Parameters
      ----------
      values : Series, DataFrame, Index subclass, or ndarray
      key : Optional[Callable], key to be called on the values array
      levels : Optional[List], if values is a MultiIndex, list of levels to
      apply the key to.
      """
      from pandas.core.indexes.api import Index
  
      if not key:
          return values
  
      if isinstance(values, ABCMultiIndex):
          return _ensure_key_mapped_multiindex(
              values, key, level=levels
          )
  
      result = key(values.copy())
      if len(result) != len(values):
          raise ValueError(
              "User-provided `key` function must not change the shape of the array."
          )
  
      try:
          if isinstance(
              values, Index
          ):  # convert to a new Index subclass, not necessarily the same
              result = Index(result)
          else:
              type_of_values = type(values)
              result = type_of_values(
                  result
              )  # try to revert to original type otherwise
      except TypeError:
          raise TypeError(
              f"User-provided `key` function returned an invalid type {type(result)} \
              which could not be converted to {type(values)}."
          )
  
      return result
  
imports: from __future__ import annotations
  from collections import defaultdict
  from typing import TYPE_CHECKING, Callable, DefaultDict, Hashable, Iterable, Sequence, cast
  import numpy
  from pandas._libs import algos, hashtable, lib
  from pandas._libs.hashtable import unique_label_indices
  from pandas._typing import AxisInt, IndexKeyFunc, Level, NaPosition, Shape, SortKind, npt
  from pandas.core.dtypes.common import ensure_int64, ensure_platform_int, is_extension_array_dtype
  from pandas.core.dtypes.generic import ABCMultiIndex, ABCRangeIndex
  from pandas.core.dtypes.missing import isna
  from pandas.core.construction import extract_array
label_desc: Use image node_id 13 for calling a global function with example usage: ensure_key_mapped(values, key, levels) and returns: result, values, _ensure_key_mapped_multiindex