How to use pip to uninstall package and install specific version of package?

You must know how to install a package with pip:

This will install the package components mainly to /usr/local/lib/python3.6/site-packages/xxx/, as well as some files to /usr/local/bin/, /usr/local/share/man/ and /usr/local/share/polkit-1/actions/.

pip3 install command installs the latest version of package. If you want to install specific version of a package, you need to uninstall the package first:

then reinstall specific version of the package: