function calculateChange(left, right) {
    let total = 0;
    for (let i = 0; i < left.length; i++) {
        total += euclideanDistance(left[i], right[i]);
    }
    return total;
}
Calculate the difference between old centroids and new centroids.

@private
@param {Array<Array<number>>} left One list of centroids.
@param {Array<Array<number>>} right Another list of centroids.
@return {number} Distance between centroids.