How to use "blender_icons_update.py"

I don’t find the instructions to generate new svg icons. When use the script nothing happens. But when I use the make lite I obtain this error.

  Generating ../../../../release/datafiles/blender_icons16.png, ../../../../release/datafiles/blender_icons16.png.c
CUSTOMBUILD : libpng warning : Image width is zero in IHDR [E:\blender-build\build_windows_Lite_x64_vc15_Release\source
\blender\editors\datafiles\bf_editor_datafiles.vcxproj]
CUSTOMBUILD : libpng warning : Image height is zero in IHDR [E:\blender-build\build_windows_Lite_x64_vc15_Release\sourc
e\blender\editors\datafiles\bf_editor_datafiles.vcxproj]
  icondir_to_png: dir 'E:/blender-build/blender/release/datafiles/blender_icons16' has no icons
  write_png: Cannot setjmp for file: 'E:/blender-build/build_windows_Lite_x64_vc15_Release/release/datafiles/blender_ic
  ons16.png'
CUSTOMBUILD : libpng error : Invalid IHDR data [E:\blender-build\build_windows_Lite_x64_vc15_Release\source\blender\edi
tors\datafiles\bf_editor_datafiles.vcxproj]
  Generating ../../../../release/datafiles/blender_icons32.png, ../../../../release/datafiles/blender_icons32.png.c
CUSTOMBUILD : libpng warning : Image width is zero in IHDR [E:\blender-build\build_windows_Lite_x64_vc15_Release\source
\blender\editors\datafiles\bf_editor_datafiles.vcxproj]
CUSTOMBUILD : libpng warning : Image height is zero in IHDR [E:\blender-build\build_windows_Lite_x64_vc15_Release\sourc
e\blender\editors\datafiles\bf_editor_datafiles.vcxproj]
CUSTOMBUILD : libpng error : Invalid IHDR data [E:\blender-build\build_windows_Lite_x64_vc15_Release\source\blender\edi
tors\datafiles\bf_editor_datafiles.vcxproj]

Any doc to see the process?

-I have windows 10
-Inkscape0.92.4 installed
-blender2.81 and 2.82
-this variables
image

These are the windows environment variables?
I think the python script assumes the exe paths to be called “blender” and “inkscape”

Ok, problem solved. It was the lack of python3.7 and reboot the cmd.

But i think that could be added to documentation. I will try to put the steps here, to at least people can find a guide in google