title: why [setBackground] not working this script?
body: <p>Here is my script-</p>
  
  <pre><code>    function dlColor()  {
        var sheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName('Sheet1');
        var columnO = sheet.getRange(2, 11, sheet.getLastRow()-1, 1).getValues();
        var colors = [];  
  
        for (var i = 0; i &lt; columnO.length; i++)
          colors.push([columnO[i][0] == 'DL' ? 'red' :
                       columnO[i][0] == '2' ? 'blue' : 'green']);
        var cell = sheet.getRange(2, 2, colors.length, 1);
        cell.setBackground(colors);
  
  
  }
  </code></pre>
  
  <p>But when I put <code>cell.setFontColor</code> that works fine. How to use cell.setBackground actually? I read Google's document but can't find it out what I've done wrong.</p>