getLargestOrAromaticCommonRing(vertexA, vertexB) {
    let commonRings = this.getCommonRings(vertexA, vertexB);
    let maxSize = 0;
    let largestCommonRing = null;

    for (var i = 0; i < commonRings.length; i++) {
      let ring = this.getRing(commonRings[i]);
      let size = ring.getSize();

      if (ring.isBenzeneLike(this.graph.vertices)) {
        return ring;
      } else if (size > maxSize) {
        maxSize = size;
        largestCommonRing = ring;
      }
    }

    return largestCommonRing;
  }
Returns the aromatic or largest ring shared by the two vertices.

@param {Vertex} vertexA A vertex.
@param {Vertex} vertexB A vertex.
@returns {(Ring|null)} If an aromatic common ring exists, that ring, else the largest (non-aromatic) ring, else null.