def METHOD_NAME():
    """
    reference:
    https://tinydb.readthedocs.io/en/stable/getting-started.html#basic-usage
    pretty-printing files:
    https://tinydb.readthedocs.io/en/stable/usage.html#storage-middleware
    main API:
    https://tinydb.readthedocs.io/en/stable/api.html
    """
    f_db = 'db_test.json'
    if os.path.exists(f_db):
        os.remove(f_db)
    # create the database in-memory
    cal_db = db.TinyDB(storage=MemoryStorage)
    query = db.Query()
    # example: create a record in the "_default" table
    # cal_db.insert({'created_gmt':datetime.utcnow().strftime("%m/%d/%Y, %H:%M:%S")})
    # create a table with metadata (provenance) about this calibration file
    file_info = {
        "system" : "oppi",
        "created_gmt" : datetime.utcnow().strftime("%m/%d/%Y, %H:%M:%S"), 
        "input_table" : "/ORSIS3302DecoderForEnergy/raw"
        }
    cal_db.table('_file_info').insert(file_info)
    # tb_info.insert(file_info)
    # add some tables with calibration constants
    table = cal_db.table('energy_cal')
    for i in range(5):
        row = {'_run':f'{i:0>4d}', 'a':i+2, 'b':i/2, 'c':i*3, 
               'tscov':int(time.time() + i*60)}
        table.insert(row) 
    table = cal_db.table('trapEmax_cal')
    for i in range(3):
        row = {'_run':f'{i:0>4d}', 'a':i+2, 'b':i/2, 'c':i*3}
        table.insert(row) 
    # pretty-print the JSON database to file
    raw_db = cal_db.storage.read()
    write_pretty(raw_db, f_db)
    # show the file as-is on disk
    with open(f_db) as f:
        print(f.read()) 