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: get_train_ind.m
    path of file: ./repos/MATLAB-Simulink-Challenge-Project-Hub/projects/Traffic Data Analysis for Modelling and Prediction of Traffic Scenarios/Utils
    
    the code of the file until where you have to start completion: function [isTrain] = get_train_ind(n, p_train, seed)
    % n (int): total number of data points

    
function [isTrain] = get_train_ind(n, p_train, seed)
    % n (int): total number of data points
    % p_train (float): in range [0,1]; percentage of training points; the
    % rest will become validation points
    % seed (int or NaN by default): random number genertor's seed
    arguments
        n (1,1) {mustBeNumeric}
        p_train (1,1) {mustBeNumeric} 
        seed = NaN
    end