def parse_sample_ids(sampleidfile):
    """
    Read the sample ID file and return a hash
    of SRS to list of SRR (SRS->[SRR])
    """

    srs={}
    with open(sampleidfile, 'r') as f:
        for l in f:
            p=l.strip().split("\t")
            if p[1] not in srs:
                srs[p[1]]=[]
            srs[p[1]].append(p[0])

    return srs