code: public Object call(Object... args) {
          List<Object> listContent = new ArrayList<Object>();
          for (Object it : args) {
              listContent.add(it);
          }
          content = listContent;
  
          return content;
      }
docs: Varargs elements as arguments to the JSON builder create a root JSON array
  <p>
  Example:
  <pre><code>
  def json = new JsonBuilder()
  def result = json 1, 2, 3
  
  assert result instanceof List
  assert json.toString() == "[1,2,3]"
  </code></pre>
  
  @param args an array of values
  @return a list of values