code: def log_every_n(level, msg, n, *args):
      
      count = _GetNextLogCountPerToken(_GetFileAndLine())
      log_if(level, msg, not (count % n), *args)
docs: Log 'msg % args' at level 'level' once per 'n' times.
  
      Logs the 1st call, (N+1)st call, (2N+1)st call,  etc.
      Not threadsafe.
  
      Args:
      level: The level at which to log.
      msg: The message to be logged.
      n: The number of times this should be called before it is logged.
      *args: The args to be substituted into the msg.