_getClusterNodeForNode(nodeId) {
    if (nodeId === undefined) return undefined;
    const clusteredNode = this.clusteredNodes[nodeId];

    // NOTE: If no cluster info found, it should actually be an error
    if (clusteredNode === undefined) return undefined;
    const clusterId = clusteredNode.clusterId;
    if (clusterId === undefined) return undefined;

    return this.body.nodes[clusterId];
  }
Determine in which cluster given nodeId resides.

If not in cluster, return undefined.

NOTE: If you know a cleaner way to do this, please enlighten me (wimrijnders).
@param {Node.id} nodeId
@returns {Node|undefined} Node instance for cluster, if present
@private