def chrom_transform(chromosome_id):
    """
    convert chromosome id from with or without `chr` suffix
    """
    if chromosome_id.startswith('chr'):
        if chromosome_id == 'chrM':
            chrom_id = 'chrM'
        else:
            chrom_id = chromosome_id.replace('chr', '')
    else:
        if chromosome_id == 'chrM':
            chrom_id = 'MT'
        else:
            chrom_id = f'chr{chromosome_id}'

    return chrom_id