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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 valid_date(x: str) -> bool: """ Retrun ``True`` if ``x`` is a valid YYYYMMDD date; otherwise return ``False``. """

    try:
        if x != dt.datetime.strptime(x, DATE_FORMAT).strftime(DATE_FORMAT):
            raise ValueError
        return True
    except ValueError:
        return False