pub fn solve(
  db_state: state.DbState,
  concept: ast.Part,
  context: ast.Part,
  threshold: Float,
  engram_var: String,
  ctx: dict.Dict(String, fact.Value),
  as_of_tx: option.Option(Int),
  as_of_valid: option.Option(Int),
) -> List(dict.Dict(String, fact.Value))