get genome lengths

def genome_lengths(fastas, info):
    """
    get genome lengths
    """
    if info is False:
        info = {}
    for genome in fastas:
        name = genome.rsplit('.', 1)[0].rsplit('/', 1)[-1].rsplit('.contigs')[0]
        if name in info:
            continue
        length = 0
        fragments = 0
        for seq in parse_fasta(genome):
            length += len(seq[1])
            fragments += 1
        info[name] = {'genome size (bp)':length, '# contigs':fragments}
    return info