code: func (ens *ENS) Register(name string) (*types.Transaction, error) {
  	parentNode, label := ensParentNode(name)
  	registrar, err := ens.getRegistrar(parentNode)
  	if err != nil {
  		return nil, err
  	}
  	return registrar.Contract.Register(&ens.TransactOpts, label, ens.TransactOpts.From)
  }
docs: // Register registers a new domain name for the caller, making them the owner of the new name.
  // Only works if the registrar for the parent domain implements the FIFS registrar protocol.