ImportError: no module named 'upip' problem

When installing additional packages for micropython on esp32, the tutorials found on the Internet are:

>>> import upip
>>> upip.install('包名')

But when actually used (my micropython version number is 1.20.0), an error will be reported:

ImportError: no module named 'upip'

Logically speaking, upip is a package installed by default. It will be automatically installed when micropython is installed on the device, but an error was reported.
After some searching, I found that 'upip' has been replaced by 'mip' after version 1.19, so you should use the following command to install the package:

>>> import mip
>>> mip.install('包名')