In order to use two versions of Python on one Windows 10 machine while keeping the 3.6 as the default environment we can use a simple trick. The final solution gives us following effect:
> python --version Python 3.6.1 > py2 > python --version Python 2.7.13 > py3 > python --version Python 3.6.1
The procedure is fairly easy and involves two simple one-line scripts. During Python 3.6 installation you should add the executable folder to environmental variables. Note the selected installation path as we’ll use it later.