code: def on_startup(self, callback: callable, polling=True, webhook=True):
          
          self._check_frozen()
          if not webhook and not polling:
              warn('This action has no effect!', UserWarning)
              return
  
          if isinstance(callback, (list, tuple, set)):
              for cb in callback:
                  self.on_startup(cb, polling, webhook)
              return
  
          if polling:
              self._on_startup_polling.append(callback)
          if webhook:
              self._on_startup_webhook.append(callback)
docs: Register a callback for the startup process
  
          :param callback:
          :param polling: use with polling
          :param webhook: use with webhook