title: Custom function not recognized
body: <p>I created  anew function in sheets from within a sheet. The function is not recognized:</p>
  
  <ol>
  <li>From within the sheet tools > script editor</li>
  <li><pre><code>function DOUBLE(input) {
    return input * 2;
  }
  </code></pre></li>
  <li><p>save</p></li>
  <li><p>Go into the sheet, enter a cell and type <code>=double(10)</code></p></li>
  <li><p>Error "unknown function 'double'"</p></li>
  </ol>