How to use the node-opcua-service-call.CallRequest function in node-opcua-service-call

ClientSession.prototype.call = function (methodsToCall, callback) {

    const self = this;

    const isArray = _.isArray(methodsToCall);
    if (!isArray) { methodsToCall = [methodsToCall]; }

    assert(_.isArray(methodsToCall));

    // Note : The client has no explicit address space and therefore will struggle to
    //        access the method arguments signature.
    //        There are two methods that can be considered:
    //           - get the object definition by querying the server
    //           - load a fake address space to have some thing to query on our end
    // const request = self._client.factory.constructObjectId("CallRequest",{ methodsToCall: methodsToCall});
    const request = new call_service.CallRequest({methodsToCall: methodsToCall});

    self.performMessageTransaction(request, function (err, response) {

        /* istanbul ignore next */
        if (err) {
            return callback(err);
        }
        assert(response instanceof call_service.CallResponse);
        callback(null, isArray ? response.results : response.results[0]);

    });

};