"die in real" error

[ProcrastinatorSal]

I'm trying to convert about 300 VMTs to VMATs. I have all VMT and TGA files in this directory:
"C:\Program Files (x86)\Steam\steamapps\common\Half-Life Alyx\content\hlvr_addons\test\materials\kairos"

Here is the output log when I try to run vmt_to_vmat.py using that directory:
https://pastebin.com/dBEE34w8

I've successfully used this script with a different set of VMT files and it worked fine. But for some reason, I'm getting this "die in real" error after the processing stage.
It does create the directory where the VMATs are supposed to go in, but the folder is empty.

[ProcrastinatorSal]

For reference, here is what one of the VMT files look like. They almost all look the same, but with different names.
"VertexlitGeneric"
{
"$basetexture" "kairos/kairos_material_0"
"$translucent" 1
}

[JackBekket]

    elif SHADER == "vr_standard":
        # die
        print("die in real")
    elif SHADER == "globallitsimple":
        # die 2.0
        print("die in real for real")
    elif SHADER == "customhero":
        # die 3: the finale
        print("death death death death death")

wrong shader, should be vr_complex