def METHOD_NAME(self, node_id: bytes32) -> None:
    if node_id in self.peer_to_peak:
        del self.peer_to_peak[node_id]
    for peak, peers in self.peak_to_peer.items():
        if node_id in peers:
            self.peak_to_peer[peak].remove(node_id)
        assert node_id not in self.peak_to_peer[peak]
    self.peers_changed.set()