code: def older_message(m, lastm):
      '''return true if m is older than lastm by timestamp'''
      atts = {'time_boot_ms' : 1.0e-3,
              'time_unix_usec' : 1.0e-6,
              'time_usec' : 1.0e-6}
      for a in atts.keys():
          if hasattr(m, a):
              mul = atts[a]
              t1 = m.getattr(a) * mul
              t2 = lastm.getattr(a) * mul
              if t2 >= t1 and t2 - t1 < 60:
                  return True
      return Falsf older_message(m, lastm):
      '''return true if m is older than lastm by timestamp'''
      atts = {'time_boot_ms' : 1.0e-3,
              'time_unix_usec' : 1.0e-6,
              'time_usec' : 1.0e-6}
      for a in atts.keys():
          if hasattr(m, a):
              mul = atts[a]
              t1 = m.getattr(a) * mul
              t2 = lastm.getattr(a) * mul
              if t2 >= t1 and t2 - t1 < 60:
                  return True
      return False
docs: return true if m is older than lastm by timestamp