How to use the biothings.utils.common.loadobj function in biothings

def load_pdb(data_folder):
    pdb_dumpfile = os.path.join(data_folder, 'gene2pdb.pyobj')
    data = loadobj(pdb_dumpfile)
    return data

def load(self):
        if self.map is None:
            self.retired2current.load()
            self.map = {}
            ensembl2entrez_li = loadobj(("ensembl_gene__2entrezgene_list.pyobj", self.db_provider()), mode='gridfs')
            #filter out those deprecated entrez gene ids
            for ensembl_id,entrez_id in ensembl2entrez_li:
                entrez_id = int(entrez_id)
                if entrez_id in self.retired2current:
                    self.map[ensembl_id] = self.retired2current.translate(entrez_id)

def load_chr_data(self):
        self.logger.info("\tLoading chromosome data from '%s'..." % self.genome)
        try:
            self._chr_data = loadobj(self.genome)
        except Exception as e:
            self.logger.info(e)
            raise
        self.logger.info("Done.")

def load_pir(data_folder):
    pir_dumpfile = os.path.join(data_folder, 'gene2pir.pyobj')
    data = loadobj(pir_dumpfile)
    return data

def load_chr_data(self):
        print("\tLoading chromosome data...", end='')
        self._chr_data = loadobj(HG19_DATAFILE)
        print("Done.")

Note that all ids are int type.
    '''
    if species_li:
        taxid_set = set([TAXONOMY[species]["tax_id"] for species in species_li])
    else:
        taxid_set = None

    orig_cwd = os.getcwd()
    os.chdir(data_folder)

    # check cache file
    _cache_file = 'geneid_d.pyobj'
    if load_cache and os.path.exists(_cache_file) and \
       file_newer(_cache_file, 'gene_info.gz') and \
       file_newer(_cache_file, 'gene_history.gz'):
        _taxid_set, out_d = loadobj(_cache_file)
        assert _taxid_set == taxid_set
        os.chdir(orig_cwd)
        return out_d

    DATAFILE = os.path.join(data_folder, 'gene_info.gz')
    if species_li:
        species_filter = lambda ld: int(ld[0]) in taxid_set and (only_for and ld[1] in only_for)
    elif only_for:
        species_filter = lambda ld: only_for and ld[1] in only_for
    else:
        species_filter = None
    geneid_li = set(tab2list(DATAFILE, 1, includefn=species_filter))

    DATAFILE = os.path.join(data_folder, 'gene_history.gz')

    if species_li:

def main(self, diff_filepath, merge_collection, field):
        diff = loadobj(diff_filepath)
        source_collection = diff['source']
        add_ids = diff['add']
        delete_ids = diff['delete']
        update_ids = [_doc['_id'] for _doc in diff['update']]
        self.add_update(source_collection, merge_collection, add_ids)
        self.add_update(source_collection, merge_collection, update_ids)
        self.delete(merge_collection, field, delete_ids)