Even macOS Sierra comes with an outdated version of python3. But if you or need the actual version of Python there is an easy to get it almost effortless in less than 5 minutes.
All you need is your terminal and Homebrew. Homebrew calls itself “The missing package manager for macOS” and it makes installing third-party packages really easy.
To install Homebrew on your computer simply copy this line to your terminal prompt:
/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
The install script will tell you what it will do before it makes any changes to your system. If you need help take a look at their install documentation.
After the installation is finished you type
brew install python3 in your terminal and you’re done.