pip3 cannot use python 3.9 code example
Example 1: install pip python 3.9
## To install Pip, first download get-pip.py from:
https://bootstrap.pypa.io/get-pip.py
## Then run the following command in the command line
## in the folder where the file has been saved.
python get-pip.py
Example 2: add python 3.9 to usr/bin
CXX="/usr/bin/g++" \
./configure --prefix=/usr \
--enable-shared \
--with-system-expat \
--with-system-ffi \
--with-ensurepip=yes &&
make