code: function _bi(value, base) {
          if (base !== undefined) {
              if (base === 256) {
                  return _bi(utils.string2bytes(value));
              }
              return new BigInteger(value, base);
          } else if (typeof value === 'string') {
              return new BigInteger(value, 10);
          } else if ((value instanceof Array) || (value instanceof Uint8Array)) {
              return new BigInteger(value);
          } else if (typeof value === 'number') {
              return new BigInteger(value.toString(), 10);
          } else {
              throw "Can't convert " + value + " to BigInteger";
          }
      }
docs: ////////////////////////////////////////////////// 
  Factory function to create a suitable BigInteger.
  
  @param value
  The value for the big integer.
  @param base {integer}
  Base of the conversion of elements in ``value``.
  @returns
  A BigInteger object.