code: func WatchAddrs(watchAddrs ...btcutil.Address) RescanOption {
  	return func(ro *rescanOptions) {
  		ro.watchAddrs = append(ro.watchAddrs, watchAddrs...)
  	}
  }
docs: // WatchAddrs specifies the addresses to watch/filter for. Each call to this
  // function adds to the list of addresses being watched rather than replacing
  // the list. Each time a transaction spends to the specified address, the
  // outpoint is added to the WatchOutPoints list.