def unique_clusters(clusters):
    """
    Find unique clusters from a cluster dict returned from find_clusters
    :param clusters:
        dictionary returned from find clusters linking sites to their clusters
    :return uniques:
        a list of all unique clusters in clusters
    """
    uniques = []
    all_clusters = set()
    for cluster in clusters.itervalues():
        if not all_clusters >= cluster:
            all_clusters |= cluster
            uniques.append(cluster)

    return uniques