"emphasize-lines" in "code-block" directive not considered

[brotkrueml]

In the following example:

..  code-block:: python
    :emphasize-lines: 3,5

    def some_function():
        interesting = False
        print('This line is highlighted.')
        print('This one is not...')
        print('...but this one is.')

does not emphasize the lines.

In the CodeNode there is also no property for this:

object(phpDocumentor\Guides\Nodes\CodeNode)#2467 (6) {
  ["classes":protected]=>
  array(0) {
  }
  ["options":protected]=>
  array(0) {
  }
  ["value":protected]=>
  string(148) "def some_function():
    interesting = False
    print('This line is highlighted.')
    print('This one is not...')
    print('...but this one is.')"
  ["startingLineNumber":"phpDocumentor\Guides\Nodes\CodeNode":private]=>
  NULL
  ["caption":"phpDocumentor\Guides\Nodes\CodeNode":private]=>
  NULL
  ["language":protected]=>
  string(6) "python"
}