code: func ExtraLeetEntropy(match match.Match, password string) float64 {
  	var subsitutions float64
  	var unsub float64
  	subPassword := password[match.I:match.J]
  	for index, char := range subPassword {
  		if string(char) != string(match.Token[index]) {
  			subsitutions++
  		} else {
  			//TODO: Make this only true for 1337 chars that are not subs?
  			unsub++
  		}
  	}
  
  	var possibilities float64
  
  	for i := float64(0); i <= math.Min(subsitutions, unsub)+1; i++ {
  		possibilities += zxcvbnmath.NChoseK(subsitutions+unsub, i)
  	}
  
  	if possibilities <= 1 {
  		return float64(1)
  	}
  	return math.Log2(possibilities)
  }
docs: // ExtraLeetEntropy calulates the added entropy provied by l33t substitustions