p5.js web editor. ' Uncaught TypeError: Cannot read property 'split' of undefined (: line 57)'

I recently started working on this project last few days from CodingTrain, however I kept running into this 'split' error. I've tried looking around how to fix it but I'm very new to JS. If anyone can help I would greatly appreciate it.

Sketch.js

 let brain;

function setup() {
  createCanvas(640, 480);
  let options = {
    inputs: 34,
    outputs: 4,
    task: 'classification',
    debug: true
  }
  brain = ml5.neuralNetwork(options);
  brain.loadData('ymca.json', dataReady);
}

function dataReady() {
  brain.normalizeData();
  brain.train({epochs: 50}, finished); 
}

function finished() {
  console.log('model trained');
  brain.save();
}

index.html 

    <!DOCTYPE html>
<html>

<head>
  <script src="https://cdnjs.cloudflare.com/ajax/libs/p5.js/0.10.2/p5.js"></script>
  <script src="https://cdnjs.cloudflare.com/ajax/libs/p5.js/0.10.2/addons/p5.sound.min.js"></script>
  <script src="https://unpkg.com/ml5@0.5.0/dist/ml5.min.js"></script>
  <link rel="stylesheet" type="text/css" href="style.css">
  <meta charset="utf-8" />

</head>

<body>
  <script src="sketch.js"></script>
</body>

</html>