code: func NewAdminContext() (*AuthContext, error) {
  	authContext, err := contextForBuiltinRole("", nil, teleport.RoleAdmin, fmt.Sprintf("%v", teleport.RoleAdmin))
  	if err != nil {
  		return nil, trace.Wrap(err)
  	}
  	return authContext, nil
  }
docs: // NewAdminContext returns new admin auth context