code: func (n *Network) OrdererOrgs() []*Organization {
  	orgsByName := map[string]*Organization{}
  	for _, o := range n.Orderers {
  		orgsByName[o.Organization] = n.Organization(o.Organization)
  	}
  
  	orgs := []*Organization{}
  	for _, org := range orgsByName {
  		orgs = append(orgs, org)
  	}
  	return orgs
  }
docs: // OrdererOrgs returns all Organization instances that own at least one
  // orderer.