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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 append_utc_timestamp(self, tag, timestamp=None, precision=3, header=False):
 """Append a field with a UTCTimestamp value. :param tag: Integer or string FIX tag number. :param timestamp: Time value, see below. :param precision: Number of decimal places: 0, 3 (ms) or 6 (us). :param header: Append to FIX header if True; default to body. The `timestamp` value should be a datetime, such as created by datetime.datetime.utcnow(); a float, being the number of seconds since midnight 1 Jan 1970 UTC, such as returned by time.time(); or, None, in which case datetime.datetime.utcnow() is used to get the current UTC time. Precision values other than zero (seconds), 3 (milliseconds), or 6 (microseconds) will raise an exception. Note that prior to FIX 5.0, only values of 0 or 3 comply with the standard."""


        return self._append_utc_datetime(tag,
                                         "%Y%m%d-%H:%M:%S",
                                         timestamp,
                                         precision,
                                         header)