code: def _add_addon_views(self):
          
          for addon in self._addon_managers:
              addon_class = dynamic_class_import(addon)
              if addon_class:
                  # Instantiate manager with appbuilder (self)
                  addon_class = addon_class(self)
                  try:
                      addon_class.pre_process()
                      addon_class.register_views()
                      addon_class.post_process()
                      self.addon_managers[addon] = addon_class
                      log.info(LOGMSG_INF_FAB_ADDON_ADDED.format(str(addon)))
                  except Exception as e:
                      log.exception(e)
                      log.error(LOGMSG_ERR_FAB_ADDON_PROCESS.format(addon, e))
docs: Registers declared addon's