mac os python version code example
Example 1: mac why is python installed in usr and application
$ pyenv global 3.7.3
# and verify it worked
$ pyenv version
3.7.3 (set by /Users/mbbroberg/.pyenv/version)
Example 2: install python in mac
brew install python3
brew install python2
Example 3: mac catallina python3
$ brew install pyenv