code: function less_than(low, high) {
      if (low.length !== high.length) {
          // Arbitrary comparison
          return low.length < high.length;
      }
  
      for (var i = 0; i < low.length; ++i) {
          if (low[i] < high[i]) {
              return true;
          } else if (low[i] > high[i]) {
              return false;
          }
      }
  
      return false;
  }
docs: Key comparison