mac python upgrade code example

Example 1: upgrade python version mc

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

Example 2: set python3 as default mac

# it is said not to do but I used it anyway, because of the conveniency
$ echo "alias python=/usr/local/bin/python3.7" >> ~/.zshrc

Example 3: mac catallina python3

$ brew install pyenv