def htrc_get_titles(metadata, vol_id):
    try:
        md = metadata[vol_id]
        return md[md.keys()[0]]['titles']

    except KeyError:
        print 'Volume ID not found:', vol_id
        raise
Return a dictionary of lines as keys and
dataset/ETHPy150Open inpho/vsm/vsm/extensions/htrc.py/htrc_get_titles--crossover with--dataset/ETHPy150Open alixander/PyScribe/pyscribe/pyscribe.py/Runner.gen_line_mapping