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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_sv_chroms(items, exclude_file):
 """Retrieve chromosomes to process on, avoiding extra skipped chromosomes. """

    exclude_regions = {}
    for region in pybedtools.BedTool(exclude_file):
        if int(region.start) == 0:
            exclude_regions[region.chrom] = int(region.end)
    out = []
    with pysam.Samfile(dd.get_align_bam(items[0]) or dd.get_work_bam(items[0]))as pysam_work_bam:
        for chrom, length in zip(pysam_work_bam.references, pysam_work_bam.lengths):
            exclude_length = exclude_regions.get(chrom, 0)
            if exclude_length < length:
                out.append(chrom)
    return out