[
  {"op": "doc", "text": "ref a registered spread by full content id"},
  {"op": "source", "role": "price", "kind": "F64"},
  {"op": "use", "ref": {"content_id": "e6982f7d4ad35dd59f1d9835e10436c193735d94501b7d10518eae0d9cd55d82"}, "name": "sp"},
  {"op": "feed", "role": "price", "into": ["sp.price"]},
  {"op": "expose", "from": "sp.spread", "as": "spread"}
]