cd /usr/bin
sudo unlink python
sudo ln -s python3 python
pytyon --versionさらにpythonのバージョンを上げたい場合はこちら。 事前にこれ入れるべし
sudo localedef -f UTF-8 -i ja_JP ja_JP
sudo apt-get update
sudo apt-get upgrade
sudo apt-get install -y gcc make wget curl git openssl build-essential libssl-dev zlib1g-dev libbz2-dev libreadline-dev libsqlite3-dev wget curl llvm libncurses5-dev libncursesw5-dev xz-utils tk-dev libffi-dev
sudo apt-get install libatlas-base-devhttps://log.mkuriki.com/raspberrypi_locale_japanese/
https://notemite.com/python/no-module-named-ctypes/
wget https://www.python.org/ftp/python/3.9.9/Python-3.9.9.tgz
tar xvf Python-3.9.9.tgz
cd Python-3.9.9
./configure --enable-optimizations
sudo make altinstallcd /usr/bin
sudo unlink python
cd /usr/local/bin
sudo ln -s python3.9 python-> OSを最新にすることに。。 https://teratail.com/questions/370448