docs: def extend(self, api, route="", base_url="", http=True, cli=True, **kwargs):
          """Adds handlers from a different Hug API to this one - to create a single API"""
          api = API(api)
  
          if http and hasattr(api, '_http'):
              self.http.extend(api.http, route, base_url, **kwargs)
  
          if cli and hasattr(api, '_cli'):
              self.cli.extend(api.cli, **kwargs)
  
          for directive in getattr(api, '_directives', {}).values():
              self.add_directive(directive)
  
          for startup_handler in (api.startup_handlers or ()):
              self.add_startup_handler(startup_handler)