code: public T random(SecureRandom random, int bits) {
              this.random = random;
              this.bits = bits;
              return self();
          }
docs: Generates a new key chain with entropy selected randomly from the given {@link SecureRandom}
  object and of the requested size in bits.  The derived seed is further protected with a user selected passphrase
  (see BIP 39).
  @param random the random number generator - use new SecureRandom().
  @param bits The number of bits of entropy to use when generating entropy.  Either 128 (default), 192 or 256.