code: def get_all_widget_classes():
      
      from leonardo.module.web.models import Widget
      _widgets = getattr(settings,
                         'WIDGETS', Widget.__subclasses__())
      widgets = []
      if isinstance(_widgets, dict):
          for group, widget_cls in six.iteritems(_widgets):
              widgets.extend(widget_cls)
      elif isinstance(_widgets, list):
          widgets = _widgets
      return load_widget_classes(widgets)
docs: returns collected Leonardo Widgets
  
      if not declared in settings is used __subclasses__
      which not supports widget subclassing