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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def events_async(key, url=None, file=None, start=None, string_content=None, end=None, fix_apple=False):
 """ Trigger an asynchronous data request. :param key: key for data source to get result later :param url: iCal URL :param file: iCal file path :param string_content: iCal content as string :param start: start date :param end: end date :param fix_apple: fix known Apple iCal issues """

    t = Thread(target=request_data, args=(key, url, file, string_content, start, end, fix_apple))

    with event_lock:
        if key not in threads:
            threads[key] = []

        threads[key].append(t)

        if not threads[key][0].is_alive():
            threads[key][0].start()