code: func namespacesFromConfig(v *viper.Viper) []centrifuge.ChannelNamespace {
  	ns := []centrifuge.ChannelNamespace{}
  	if !v.IsSet("namespaces") {
  		return ns
  	}
  	v.UnmarshalKey("namespaces", &ns)
  	return ns
  }
docs: // namespacesFromConfig allows to unmarshal channel namespaces.