code: func (pairs comparablePrincipalSetPairs) ToMergedPrincipalSets() ComparablePrincipalSets {
  	var res ComparablePrincipalSets
  	for _, pair := range pairs {
  		res = append(res, pair.MergeWithPlurality())
  	}
  	return res
  }
docs: // ToPrincipalSets converts the comparablePrincipalSetPairs to ComparablePrincipalSets
  // while taking into account plurality of each pair