Cannot run the scripts through command line

[ibo-o]

When I run this python run-filter.py trial.glyphs Zebra

I get this error message. Even though it shows the filter as available, writing the name of it doesn't prompt the script.

Couldn't find filter 'Zebra'.
Try one of: 80sFade, Beastly, BrokenFax, Bubble, Burned, Dirt, Distressed, DoodleShadow, DoodleTriangles, Gemstones, Glitch, GlitchPop, Iso, Lines, Maps, MarkerHatch, Maze, Microbe, MoonRocks, Pixels, Puddles, Scribble, SeaCamouflage, SprayPaint, Storm, Vinyl, WetPaint, Zebra

Am I missing something?