code: func (s *RegistrarService) RegisterDomain(accountID string, domainName string, request *DomainRegisterRequest) (*domainRegistrationResponse, error) {
  	path := versioned(fmt.Sprintf("/%v/registrar/domains/%v/registrations", accountID, domainName))
  	registrationResponse := &domainRegistrationResponse{}
  
  	// TODO: validate mandatory attributes RegistrantID
  
  	resp, err := s.client.post(path, request, registrationResponse)
  	if err != nil {
  		return nil, err
  	}
  
  	registrationResponse.HttpResponse = resp
  	return registrationResponse, nil
  }
docs: // RegisterDomain registers a domain name.
  //
  // See https://developer.dnsimple.com/v2/registrar/#register