code: def append_time(self, tag, timestamp=None, precision=3, utc=True,
                      header=False):
          
  
          warnings.warn("simplefix.FixMessage.append_time() is deprecated. "
                        "Use append_utc_timestamp() or append_tz_timestamp() "
                        "instead.", DeprecationWarning)
          if not timestamp:
              t = datetime.datetime.utcnow()
  
          elif type(timestamp) is float:
              if utc:
                  t = datetime.datetime.utcfromtimestamp(timestamp)
              else:
                  t = datetime.datetime.fromtimestamp(timestamp)
  
          else:
              t = timestamp
  
          s = t.strftime("%Y%m%d-%H:%M:%S")
          if precision == 3:
              s += ".%03d" % (t.microsecond / 1000)
          elif precision == 6:
              s += ".%06d" % t.microsecond
          elif precision != 0:
              raise ValueError("Precision should be one of 0, 3 or 6 digits")
  
          return self.append_pair(tag, s, header=header)
docs: Append a time field to this message.
  
          :param tag: Integer or string FIX tag number.
          :param timestamp: Time (see below) value to append, or None for now.
          :param precision: Number of decimal digits.  Zero for seconds only,
          three for milliseconds, 6 for microseconds.  Defaults to milliseconds.
          :param utc: Use UTC if True, local time if False.
          :param header: Append to header if True; default to body.
  
          THIS METHOD IS DEPRECATED!
          USE append_utc_timestamp() OR append_tz_timestamp() INSTEAD.
  
          Append a timestamp in FIX format from a Python time.time or
          datetime.datetime value.
  
          Note that prior to FIX 5.0, precision must be zero or three to be
          compliant with the standard.