Taxonomy Collections

Hi. I'm trying to make a taxonomy collection that only shows pages that match ALL taxonomy in a collection. What I have right now is:

content:
  items: @taxonomy: {tag:[featured, branding], category[project]}

I've gone through the taxonomy collections docs and that's what I've figured would work but doesn't. Any idea on making this possible?

I see missing a : after category, and also check you are using the correct indentation, it matters.