code: func (b *RWSetBuilder) getTxPvtReadWriteSet() *TxPvtRwSet {
  	sortedNsPvtBuilders := []*nsPvtRwBuilder{}
  	util.GetValuesBySortedKeys(&(b.pvtRwBuilderMap), &sortedNsPvtBuilders)
  
  	var nsPvtRwSets []*NsPvtRwSet
  	for _, nsPvtRwBuilder := range sortedNsPvtBuilders {
  		nsPvtRwSets = append(nsPvtRwSets, nsPvtRwBuilder.build())
  	}
  	if len(nsPvtRwSets) == 0 {
  		return nil
  	}
  	return &TxPvtRwSet{NsPvtRwSet: nsPvtRwSets}
  }
docs: // getTxPvtReadWriteSet returns the private read-write set