Work with Data in D3: Right Output with Error

Tell us what’s happening:
I am quite sure the code is correct and it is displaying 9 html li’s as per the length of the array. But I am getting:
// running tests

Your document should have 9 h2 elements.

Cannot read property ‘length’ of null

// tests completed

Your code so far

    const dataset = [12, 31, 22, 17, 25, 18, 29, 14, 9];
    // Add your code below this line"body").selectAll("h2")
      .text("New Title")
    // Add your code above this line

Your browser information:

User Agent is: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/74.0.3729.169 Safari/537.36.

Link to the challenge: