docs: function writeReportCfg (permAddr, auxId, attr, cfg, callback) {
      var shepherd = this,
          realAddr = helper.parsePermAddr(permAddr),
          dev = shepherd.find(realAddr.clientName),
          path = auxId + '/' + attr,
          enable = cfg.enable,
          err = null;
  
      delete cfg.enable;
      
      function invokeCb(e, cb) {
          if (e)
              cb(e, false);
          else 
              cb(null, true);
      }
  
      if (dev) {
          if (!_.isEmpty(cfg) && enable === true) {
              dev.writeAttrsReq(path, cfg, function (err, rsp) {
                  err = err || helper.rspStatusChk(rsp.status);
  
                  if (err) {
                      callback(err, false);
                  } else {
                      dev.observeReq(path, function (err, rsp) {
                          err = err || helper.rspStatusChk(rsp.status);
  
                          invokeCb(err, callback);
                      });
                  }
              });
          } else if (!_.isEmpty(cfg) && enable === false) {
              dev.writeAttrsReq(path, cfg, function (err, rsp) {
                  err = err || helper.rspStatusChk(rsp.status);
  
                  if (err) {
                      callback(err, false);
                  } else {
                      dev.cancelObserveReq(path, function (err, rsp) {
                          err = err || helper.rspStatusChk(rsp.status);
  
                          invokeCb(err, callback);
                      });
                  }
              });
          } else if (!_.isEmpty(cfg)) {
              dev.writeAttrsReq(path, cfg, function (err, rsp) {
                  err = err || helper.rspStatusChk(rsp.status);
  
                  invokeCb(err, callback);
              });
          } else if (_.isEmpty(cfg) && enable === true) {
              dev.observeReq(path, function (err, rsp) {
                  err = err || helper.rspStatusChk(rsp.status);
  
                  invokeCb(err, callback);
              });
          } else if (_.isEmpty(cfg) && enable === false) {
              dev.cancelObserveReq(path, function (err, rsp) {
                  err = err || helper.rspStatusChk(rsp.status);
  
                  invokeCb(err, callback);
              });
          }
      } else {
          callback(new Error('Device not found.'));
      }
  }