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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_location_list(interval_bed):
 """Retrieve list of locations to analyze from input BED file. """

    import pybedtools
    regions = collections.OrderedDict()
    for region in pybedtools.BedTool(interval_bed):
        regions[str(region.chrom)] = None
    return regions.keys()