Why does plotly.validate not pass for this layout

Hi,

I am checking to see how the plotly.validate functions work. At the moment I have this following code for my layout:

var trace1 = {
  x: [1, 2, 3, 4],
  y: [10, 15, 13, 17],
  mode: 'markers',
  type: 'scatter'
};

var trace2 = {
  x: [2, 3, 4, 5],
  y: [16, 5, 11, 9],
  mode: 'lines',
  type: 'scatter'
};

var traces= [
  {
    name: "test",
    type: "histogram",
    xaxis: "x",
    yaxis: "y",
    x: [1,2,3],
  }
] 

const layout = 
      {
        "title":"XY.Histogram.Basic",
       "legend":{
         "showlegend":true,
         "x":0,
         "y":1,
         "orientation":"v"
       },
       "height":500,
       "width":800,
       "grid":{
         "rows":1,
         "columns":1,
         "pattern":"independent"
       },
       "xaxis":{
         "title":"x",
         "side":"",
         "overlaying":"",
         "showgrid":true,
         "zeroline":false,
         "showline":false
       },"yaxis":{
         "title":"y",
         "side":"",
         "overlaying":"",
         "showgrid":true,
         "zeroline":false,
         "showline":false
       }
      }

console.log(Plotly.validate(traces, layout))

If I run this code as below, it console logs an error:

See the Pen Plotly.js Line and Scatter Plot by fuzzy (@fkE3) on CodePen.

Why is validation failing here? Any guidance is much appreciated

remove the last comma from here x: [1,2,3],