def guest_inspect_vnics(self, userid_list):
        """Get the vnics statistics of the guest virtual machines

        :param userid_list: a single userid string or a list of guest userids
        :returns: dictionary describing the vnics statistics of the vm
                  in the form
                  {'UID1':
                  [{
                  'vswitch_name': xx,
                  'nic_vdev': xx,
                  'nic_fr_rx': xx,
                  'nic_fr_tx': xx,
                  'nic_fr_rx_dsc': xx,
                  'nic_fr_tx_dsc': xx,
                  'nic_fr_rx_err': xx,
                  'nic_fr_tx_err': xx,
                  'nic_rx': xx,
                  'nic_tx': xx
                  },
                  ],
                  'UID2':
                  [{
                  'vswitch_name': xx,
                  'nic_vdev': xx,
                  'nic_fr_rx': xx,
                  'nic_fr_tx': xx,
                  'nic_fr_rx_dsc': xx,
                  'nic_fr_tx_dsc': xx,
                  'nic_fr_rx_err': xx,
                  'nic_fr_tx_err': xx,
                  'nic_rx': xx,
                  'nic_tx': xx
                  },
                  ]
                  }
                  for the guests that are shutdown or not exist, no data
                  returned in the dictionary
        """
        if not isinstance(userid_list, list):
            userid_list = [userid_list]
        action = "get the vnics statistics of guest '%s'" % str(userid_list)
        with zvmutils.log_and_reraise_sdkbase_error(action):
            return self._monitor.inspect_vnics(userid_list)