Connect to seqcluster to run cluster with python directly

def _cluster(bam_file, ma_file, out_dir, reference, annotation_file=None):
    """
    Connect to seqcluster to run cluster with python directly
    """
    seqcluster = op.join(get_bcbio_bin(), "seqcluster")
    # cl = ["cluster", "-o", out_dir, "-m", ma_file, "-a", bam_file, "-r", reference]
    if annotation_file:
        annotation_file = "-g " + annotation_file
    else:
        annotation_file = ""

    if not file_exists(op.join(out_dir, "counts.tsv")):
        cmd = ("{seqcluster} cluster -o {out_dir} -m {ma_file} -a {bam_file} -r {reference} {annotation_file}")
        do.run(cmd.format(**locals()), "Running seqcluster.")
    counts = op.join(out_dir, "counts.tsv")
    stats = op.join(out_dir, "read_stats.tsv")
    json = op.join(out_dir, "seqcluster.json")
    return {'out_dir': out_dir, 'count_file': counts, 'stat_file': stats, 'json': json}