找不到错误(Project Euler #8 (Scala))

val number = "73167176531330624919225119674426574742355349194934" +
             "96983520312774506326239578318016984801869478851843" +
             "85861560789112949495459501737958331952853208805511" +
             "12540698747158523863050715693290963295227443043557" +
             "66896648950445244523161731856403098711121722383113" +
             "62229893423380308135336276614282806444486645238749" +
             "30358907296290491560440772390713810515859307960866" +
             "70172427121883998797908792274921901699720888093776" +
             "65727333001053367881220235421809751254540594752243" +
             "52584907711670556013604839586446706324415722155397" +
             "53697817977846174064955149290862569321978468622482" +
             "83972241375657056057490261407972968652414535100474" +
             "82166370484403199890008895243450658541227588666881" +
             "16427171479924442928230863465674813919123162824586" +
             "17866458359124566529476545682848912883142607690042" +
             "24219022671055626321111109370544217506941658960408" +
             "07198403850962455444362981230987879927244284909188" +
             "84580156166097919133875499200524063689912560717606" +
             "05886116467109405077541002256983155200055935729725" +
             "71636269561882670428252483600823257530420752963450"

def findMaxProduct(number: String, length: Int): Long = {
  var maxProduct: Long = 0
  for (i <- 0 to number.length - length) {
    val substring = number.substring(i, i + length)
    val product = substring.map(_.asDigit.toLong).product
    if (product > maxProduct) {
      maxProduct = product
    }
  }
  maxProduct
}

val maxLength = 13
val maxProduct = findMaxProduct(number, maxLength)
println(s"The maximum product of $maxLength consecutive digits is: $maxProduct")