This function usually runs as process on the background.

    It runs ``function(*function_arguments)`` and then stores them in REST API
    storage.

    Warning:
        This function puts data into DB, isntead of returning them.

    Args:
        url_key (str): Key which will be used for database lookup.
        property_name (str): Name of the property used to store data.
        function (obj): Function used to load the data.
        function_arguments (list): List of parameters for function which will
            be called to retreive data.
        error_log_path (str): If set, log errors into this file, otherwise
            stderr.

def worker(url_key, property_name, function, function_arguments):
    """
    This function usually runs as process on the background.

    It runs ``function(*function_arguments)`` and then stores them in REST API
    storage.

    Warning:
        This function puts data into DB, isntead of returning them.

    Args:
        url_key (str): Key which will be used for database lookup.
        property_name (str): Name of the property used to store data.
        function (obj): Function used to load the data.
        function_arguments (list): List of parameters for function which will
            be called to retreive data.
        error_log_path (str): If set, log errors into this file, otherwise
            stderr.
    """
    # this may take some time, hence outside transaction manager
    error_msg = None
    try:
        data = function(*function_arguments)
    except Exception as e:
        data = []
        error_msg = "Error: " + traceback.format_exc().strip()
        error_msg += "\n" + str(e.message)

    # handle logging of possible error message
    if error_msg:
        logger.error(error_msg)
        error_msg = None

    func_name = str(function.__name__)
    logger.info(
        "Attempting to save output from `%s`." % func_name
    )

    # save `data` into RequestInfo object property
    return _save_to_database(
        url=url_key,
        property_name=property_name,
        data=data
    )