pip is broken after pip upgrade – ModuleNotFoundError: No module named ‘tomllib’

I upgraded PIP, now any call of PIP results in an error. Any suggestions in Internet to restore PIP … are using PIP itself. I mean: how can I use PIP to resolve the problem if excatly the PIP is broken? Could you please suggest, how could I restore previous PIP version if it has been uninstalled?

python3.11 -m pip install --upgrade --force-reinstall pip
Traceback (most recent call last):
  File "<frozen runpy>", line 198, in _run_module_as_main
  File "<frozen runpy>", line 88, in _run_code
  File "/usr/local/lib/python3.11/site-packages/pip/__main__.py", line 24, in <module>
    sys.exit(_main())
             ^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/pip/_internal/cli/main.py", line 47, in main
    from pip._internal.cli.autocompletion import autocomplete
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/pip/_internal/cli/autocompletion.py", line 12, in <module>
    from pip._internal.cli.main_parser import create_main_parser
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/pip/_internal/cli/main_parser.py", line 11, in <module>
    from pip._internal.build_env import get_runnable_pip
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/pip/_internal/build_env.py", line 22, in <module>
    from pip._internal.cli.spinners import open_rich_spinner, open_spinner
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/pip/_internal/cli/spinners.py", line 21, in <module>
    from pip._internal.utils.compat import WINDOWS
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/pip/_internal/utils/compat.py", line 71, in <module>
    import tomllib
    ^^^^^^^^^^^^^^
ModuleNotFoundError: No module named 'tomllib'