docs: function(numbers, opt_factor) {
        var factor = opt_factor || 1e5;
  
        var numbersLength = numbers.length;
        for (var i = 0; i < numbersLength; ++i) {
          numbers[i] = Math.round(numbers[i] * factor);
        }
  
        return this.encodeSignedIntegers(numbers);
      }