You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: nodeListInfo.m
    path of file: ./repos/MATLAB-NS3/scenarios/truckPlatooning
    
    the code of the file until where you have to start completion: classdef nodeListInfo < handle
    % For each node, persistent arrays in each function store node related
    % information which can be get/set when required. The index in the arrays
    % defines the node id. For example: if current acceleration o
    
function txCount = nodeTxCount(vehicleId, pktCount)
            persistent txCountList;
            if(nargin >= 2)  % Using as a set function.
                if(pktCount>0)
                    txCountList(vehicleId) = txCountList(vehicleId) + ...
                        pktCount;
                else
                    txCountList(vehicleId) = 0;
                end