code: func (n *collElgNotifier) elgEnabledCollNames(ledgerID string,
  	existingPkg, postCommitPkg *common.CollectionConfigPackage) ([]string, error) {
  
  	collectionNames := []string{}
  	exisingConfs := retrieveCollConfs(existingPkg)
  	postCommitConfs := retrieveCollConfs(postCommitPkg)
  	existingConfMap := map[string]*common.StaticCollectionConfig{}
  	for _, existingConf := range exisingConfs {
  		existingConfMap[existingConf.Name] = existingConf
  	}
  
  	for _, postCommitConf := range postCommitConfs {
  		collName := postCommitConf.Name
  		existingConf, ok := existingConfMap[collName]
  		if !ok { // brand new collection
  			continue
  		}
  		membershipEnabled, err := n.elgEnabled(ledgerID, existingConf.MemberOrgsPolicy, postCommitConf.MemberOrgsPolicy)
  		if err != nil {
  			return nil, err
  		}
  		if !membershipEnabled {
  			continue
  		}
  		// not an existing member and added now
  		collectionNames = append(collectionNames, collName)
  	}
  	return collectionNames, nil
  }
docs: // elgEnabledCollNames returns the names of the collections for which the peer is not eligible as per 'existingPkg' and is eligible as per 'postCommitPkg'