code: def get_default_classes(self):
          
          default_classes = super(Tab, self).get_default_classes()
          if self.is_active():
              default_classes.extend(CSS_ACTIVE_TAB_CLASSES)
          if not self._enabled:
              default_classes.extend(CSS_DISABLED_TAB_CLASSES)
          return default_classes
docs: Returns a list of the default classes for the tab.
  
          Defaults to and empty list (``[]``), however additional classes may
          be added depending on the state of the tab as follows:
  
          If the tab is the active tab for the tab group, in which
          the class ``"active"`` will be added.
  
          If the tab is not enabled, the classes the class ``"disabled"``
          will be added.