def set_fwd_channel_anns_ts(self, channel_anns: List[GossipForwardingMessage]) \
        -> List[GossipForwardingMessage]:
        """Set the timestamps of the passed channel announcements from the corresponding policies"""
        timestamped_chan_anns: List[GossipForwardingMessage] = []
        with self.lock:
            policies = self._policies.copy()
            channels = self._channels.copy()

        for chan_ann in channel_anns:
            if chan_ann.timestamp is not None:
                timestamped_chan_anns.append(chan_ann)
                continue

            scid = chan_ann.scid
            if (channel_info := channels.get(scid)) is None:
                continue

            policy1 = policies.get((channel_info.node1_id, scid))
            policy2 = policies.get((channel_info.node2_id, scid))
            potential_timestamps = []
            for policy in [policy1, policy2]:
                if policy is not None:
                    potential_timestamps.append(policy.timestamp)
            if not potential_timestamps:
                continue
            chan_ann.timestamp = min(potential_timestamps)
            timestamped_chan_anns.append(chan_ann)
        return timestamped_chan_anns
Set the timestamps of the passed channel announcements from the corresponding policies
electrum/channel_db.py