async def rebroadcast_event(self, event: Event, server_relays: Sequence[str]):
        """If the relays of the origin server are different from our relays we rebroadcast the
        event to our relays so it gets spread more widely."""
        if not server_relays:
            return
        rebroadcast_relays = [relay for relay in self.relay_manager.relays if
                              relay.url not in server_relays]
        for relay in rebroadcast_relays:
            try:
                res = await relay.add_event(event, check_response=True)
            except Exception as e:
                self.logger.debug(f"failed to rebroadcast event to {relay.url}: {e}")
                continue
            self.logger.debug(f"rebroadcasted event to {relay.url}: {res}")
If the relays of the origin server are different from our relays we rebroadcast the
        event to our relays so it gets spread more widely.
electrum/submarine_swaps.py