code: def add_point(self, reading_id, uptime=None, utc=None, is_break=False):
          
  
          if reading_id == 0:
              return
  
          if uptime is None and utc is None:
              return
  
          if uptime is not None and uptime & (1 << 31):
              if utc is not None:
                  return
  
              uptime &= ~(1 << 31)
  
              utc = self.convert_rtc(uptime)
              uptime = None
  
          anchor = _TimeAnchor(reading_id, uptime, utc, is_break, exact=utc is not None)
  
          if anchor in self._anchor_points:
              return
  
          self._anchor_points.add(anchor)
          self._prepared = False
docs: Add a time point that could be used as a UTC reference.