message: also look for 4 and 7 member sugar rings
diff: @@ -22,7 +22,12 @@ import { UnitRings, UnitRing } from '../unit/rings';
  import { ElementIndex } from '../../model/indexing';
  const C = ElementSymbol('C'), O = ElementSymbol('O');
  -const SugarRingFps = [UnitRing.elementFingerprint([C, C, C, C, C, O]), UnitRing.elementFingerprint([C, C, C, C, O])]
  +const SugarRingFps = [
  + UnitRing.elementFingerprint([C, C, C, O]),
  + UnitRing.elementFingerprint([C, C, C, C, O]),
  + UnitRing.elementFingerprint([C, C, C, C, C, O]),
  + UnitRing.elementFingerprint([C, C, C, C, C, C, O]),
  +]
  function getAnomericCarbon(unit: Unit.Atomic, ringAtoms: ArrayLike<StructureElement.UnitIndex>): ElementIndex {
  let indexHasTwoOxygen = -1, indexHasOxygenAndCarbon = -1, indexHasC1Name = -1, indexIsCarbon = -1
  