code: func IsTransactionHashWithMWM(trytes Trytes, mwm uint) bool {
  	correctLength := IsTrytesOfExactLength(trytes, HashTrytesSize)
  	if !correctLength {
  		return false
  	}
  
  	trits := MustTrytesToTrits(trytes)
  	for _, trit := range trits[len(trits)-int(mwm):] {
  		if trit != 0 {
  			return false
  		}
  	}
  	return true
  }
docs: // IsTransactionHashWithMWM checks if input is correct transaction hash (81 trytes) with given MWM