Here is how I enable +python and +lua and +python3 in win7

[wsdjeg]

SpaceVim Health checking :

SpaceVim clipboard support check report:
Checking +clipboard:
SUCCEED!
SpaceVim environment check report:
Current progpath: gvim.exe(C:\Program Files\vim80\gvim.exe)
version: 800
OS: Windows
[shell, shellcmdflag, shellslash]: ['C:\Windows\system32\cmd.exe', '/c', 0]
SpaceVim lua support check report:
Checking +lua:
SUCCEED!
SpaceVim python support check report:
Checking +python3:
SUCCEED!
Checking +python:
SUCCEED!

[Gabirel]

The right way to configure:

set pythonthreedll=python36.dll
set pythondll=python27.dll

It has default value. That's why I can make vim support python2 and python3 at the same time.

[wsdjeg]

it is based on the output of

py -2 --version
py -3 --version

[Gabirel]

Summary:
Test:

echo has('python')
echo has('python3')

If your vim doesn't have python support, please see the following steps:

py -2 --version
py -3 --version

Based the version of python, set default value of python support for vim.

set pythonthreedll=python36.dll
set pythondll=python27.dll