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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 run_mutation_aggregator(job, mutation_results, univ_options):
 """ Aggregate all the called mutations. :param dict mutation_results: Dict of dicts of the various mutation callers in a per chromosome format :param dict univ_options: Dict of universal options used by almost all tools :returns: fsID for the merged mutations file :rtype: toil.fileStore.FileID """

    # Setup an input data structure for the merge function
    out = {}
    for chrom in mutation_results['mutect'].keys():
        out[chrom] = job.addChildJobFn(merge_perchrom_mutations, chrom, mutation_results,
                                       univ_options).rv()
    merged_snvs = job.addFollowOnJobFn(merge_perchrom_vcfs, out, 'merged', univ_options)
    job.fileStore.logToMaster('Aggregated mutations for %s successfully' % univ_options['patient'])
    return merged_snvs.rv()