code: func LvlFilterHandler(maxLvl Lvl, h Handler) Handler {
  	return FilterHandler(func(r *Record) (pass bool) {
  		return r.Lvl <= maxLvl
  	}, h)
  }
docs: // LvlFilterHandler returns a Handler that only writes
  // records which are less than the given verbosity
  // level to the wrapped Handler. For example, to only
  // log Error/Crit records:
  //
  //     log.LvlFilterHandler(log.LvlError, log.StdoutHandler)
  //