code: def remove_all_callbacks(self):
          
          for cb_id in list(self._next_tick_callback_removers.keys()):
              self.remove_next_tick_callback(cb_id)
          for cb_id in list(self._timeout_callback_removers.keys()):
              self.remove_timeout_callback(cb_id)
          for cb_id in list(self._periodic_callback_removers.keys()):
              self.remove_periodic_callback(cb_id)
docs: Removes all registered callbacks.