How to use the big-integer.lcm function in big-integer

export function lcm(x: BigInteger, y: BigInteger): BigInteger {
  return bigInteger.lcm(x, y)
}

static generate(keysize) {
    const e = bigInt(65537);
    let p;
    let q;
    let totient;
  
    do {
      p = this.randomPrime(keysize / 2);
      q = this.randomPrime(keysize / 2);
      totient = bigInt.lcm(
        p.prev(),
        q.prev()
      );
    } while (bigInt.gcd(e, totient).notEquals(1) || p.minus(q).abs().shiftRight(keysize / 2 - 100).isZero());

    return {
      e, 
      n: p.multiply(q),
      d: e.modInv(totient),
    };
  }