ImportError: cannot import name ‘enable_halving_search_cv’ from ‘sklearn.experimental’ (C:\Users\Administrator\anaconda3\lib\site-packages\sklearn\experimental\__init__.py)

Describe the bug

Cannot import enable_halving_search_cv from sklearn as documented in sklearn manual.

Steps/Code to Reproduce

Example:

from sklearn.experimental import enable_halving_search_cv
from sklearn.model_selection import HalvingRandomSearchCV

Actual Results

ImportError: cannot import name 'enable_halving_search_cv' from 'sklearn.experimental' (C:\Users\Administrator\anaconda3\lib\site-packages\sklearn\experimental\__init__.py)

Versions

System:
python: 3.8.5 (default, Sep 3 2020, 21:29:08) [MSC v.1916 64 bit (AMD64)]
executable: C:\Users\Administrator\anaconda3\python.exe
machine: Windows-10-10.0.18362-SP0

Python dependencies:
pip: 20.2.4
setuptools: 50.3.1.post20201107
sklearn: 0.23.2
numpy: 1.19.2
scipy: 1.5.2
Cython: 0.29.21
pandas: 1.1.3
matplotlib: 3.3.2
joblib: 0.17.0
threadpoolctl: 2.1.0

Built with OpenMP: True