Trunk broken 24.7.16 "UnboundLocalError: local variable 'ret_value' referenced before assignment"

Trying to run trunk.

Traceback (most recent call last):
  File "openlp.py", line 44, in <module>
    main()
  File "E:\bzr\openlp\trunk\openlp\core\__init__.py", line 392, in main
    sys.exit(application.run(qt_args))
  File "E:\bzr\openlp\trunk\openlp\core\__init__.py", line 143, in run
    Registry().execute('bootstrap_post_set_up')
  File "E:\bzr\openlp\trunk\openlp\core\common\registry.py", line 137, in execute
    result = function(*args, **kwargs)
  File "E:\bzr\openlp\trunk\openlp\core\ui\thememanager.py", line 155, in bootstrap_post_set_up
    self.load_themes()
  File "E:\bzr\openlp\trunk\openlp\core\ui\thememanager.py", line 492, in load_themes
    self._push_themes()
  File "E:\bzr\openlp\trunk\openlp\core\ui\thememanager.py", line 498, in _push_themes
    Registry().execute('theme_update_list', self.get_themes())
  File "E:\bzr\openlp\trunk\openlp\core\common\registry.py", line 137, in execute
    result = function(*args, **kwargs)
  File "E:\bzr\openlp\trunk\openlp\core\ui\servicemanager.py", line 1671, in update_theme_list
    self.renderer.set_service_theme(self.service_theme)
  File "E:\bzr\openlp\trunk\openlp\core\lib\renderer.py", line 177, in set_service_theme
    self._set_theme(service_theme_name)
  File "E:\bzr\openlp\trunk\openlp\core\lib\renderer.py", line 112, in _set_theme
    theme_data = self.theme_manager.get_theme_data(theme_name)
  File "E:\bzr\openlp\trunk\openlp\core\ui\thememanager.py", line 520, in get_theme_data
    return self._create_theme_from_xml(xml, self.path)
  File "E:\bzr\openlp\trunk\openlp\core\ui\thememanager.py", line 729, in _create_theme_from_xml
    theme.parse(theme_xml)
  File "E:\bzr\openlp\trunk\openlp\core\lib\theme.py", line 415, in parse
    self.parse_xml(str(xml))
  File "E:\bzr\openlp\trunk\openlp\core\lib\theme.py", line 462, in parse_xml
    self._create_attr('theme', element.tag, element.text)
  File "E:\bzr\openlp\trunk\openlp\core\lib\theme.py", line 491, in _create_attr
    reject, master, element, value = self._translate_tags(master, element, value)
  File "E:\bzr\openlp\trunk\openlp\core\lib\theme.py", line 485, in _translate_tags
    return False, master, element, ret_value
UnboundLocalError: local variable 'ret_value' referenced before assignment