docs: def grant_user_to_vswitch(self, vswitch_name, userid):
          """Set vswitch to grant user."""
          smt_userid = zvmutils.get_smt_userid()
          requestData = ' '.join((
              'SMAPI %s API Virtual_Network_Vswitch_Set_Extended' % smt_userid,
              "--operands",
              "-k switch_name=%s" % vswitch_name,
              "-k grant_userid=%s" % userid,
              "-k persist=YES"))
  
          try:
              self._request(requestData)
          except exception.SDKSMTRequestFailed as err:
              LOG.error("Failed to grant user %s to vswitch %s, error: %s"
                        % (userid, vswitch_name, err.format_message()))
              self._set_vswitch_exception(err, vswitch_name)