how to update python from terminal code example

Example 1: upgrade python version mc

brew install python3
brew update && brew upgrade python
alias python=/usr/local/bin/python3

Example 2: install python3

echo This is for linux. (debian/unbuntu)
sudo apt install build-essential zlib1g-dev libncurses5-dev libgdbm-dev libnss3-dev libssl-dev libreadline-dev libffi-dev wget
curl -O https://www.python.org/ftp/python/3.7.4/Python-3.7.4.tar.xz
tar -xf Python-3.7.4.tar.xz
cd Python-3.7.4
./configure --enable-optimizations
make
sudo make altinstall
python3.7 --version
cd ../