As of Aug 14, 2023 deadsnakes ppa remove Ubuntu 18 bionic support for Python3.9 Therefore, We have to manually make it.
must be root user
py_version=3.9.17
apt install -y gcc make openssl libssl-dev zlib1g zlib1g-dev libffi-dev
cd /root
curl -O https://www.python.org/ftp/python/${py_version}/Python-${py_version}.tgz
tar -zxvf Python-${py_version}.tgz
cd Python-${py_version}
./configure --prefix=/usr/local/python/Python-${py_version} --with-ensurepip=install
make
make install
cd ..
rm -rf Python-${py_version} Python-${py_version}.tgz
ln -s /usr/local/python/Python-${py_version}/bin/* /usr/local/bin/