code: func (s *DomainsService) RemoveCollaborator(accountID string, domainIdentifier string, collaboratorID int64) (*collaboratorResponse, error) {
  	path := versioned(collaboratorPath(accountID, domainIdentifier, collaboratorID))
  	collaboratorResponse := &collaboratorResponse{}
  
  	resp, err := s.client.delete(path, nil, nil)
  	if err != nil {
  		return nil, err
  	}
  
  	collaboratorResponse.HttpResponse = resp
  	return collaboratorResponse, nil
  }
docs: // RemoveCollaborator PERMANENTLY deletes a domain from the account.
  //
  // See https://developer.dnsimple.com/v2/domains/collaborators#remove