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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 parse_date(ims):
 """ Parse rfc1123, rfc850 and asctime timestamps and return UTC epoch. """

    try:
        ts = email.utils.parsedate_tz(ims)
        return time.mktime(ts[:8] + (0,)) - (ts[9] or 0) - time.timezone
    except (TypeError, ValueError, IndexError):
        return None