code: func NewDeliverClientForOrderer(channelID string) (*DeliverClient, error) {
  	var tlsCertHash []byte
  	oc, err := NewOrdererClientFromEnv()
  	if err != nil {
  		return nil, errors.WithMessage(err, "failed to create deliver client")
  	}
  
  	dc, err := oc.Deliver()
  	if err != nil {
  		return nil, errors.WithMessage(err, "failed to create deliver client")
  	}
  	// check for client certificate and create hash if present
  	if len(oc.Certificate().Certificate) > 0 {
  		tlsCertHash = util.ComputeSHA256(oc.Certificate().Certificate[0])
  	}
  	ds := &ordererDeliverService{dc}
  	o := &DeliverClient{
  		Service:     ds,
  		ChannelID:   channelID,
  		TLSCertHash: tlsCertHash,
  	}
  	return o, nil
  }
docs: // NewDeliverClientForOrderer creates a new DeliverClient from an OrdererClient