def get_geneid_to_pubmeds(file_name, tax_id = "9606"):
    """
    To parse gene2pubmed file from NCBI 
    """
    f = open(file_name)
    geneid_to_pubmeds = {}
    f.readline()
    for line in f:
        tax, geneid, pubmed_id = line.strip().split("\t")
        if tax != tax_id:
            continue
        geneid_to_pubmeds.setdefault(geneid, set()).add(pubmed_id)
    return geneid_to_pubmeds